JP3357231B2 - Leather-like sheet with good handling properties - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leather-like sheet having non-slip properties, and more particularly to a leather-like sheet suitable for sports gloves, balls for American football and basketball, and the like.

[0002]

2. Description of the Related Art Conventionally, various methods have been proposed as methods for obtaining a sheet having non-slip properties. For example, Japanese Patent Publication No. 7-30285 discloses a sheet composition containing a polyurethane resin having a hydroxyl group in a molecule, a liquid rubber having a hydroxyl group in a molecule, an inorganic or organic filler, and an isocyanate prepolymer. The method of coating on the surface is disclosed in Japanese Utility Model Application Laid-Open No. 63-197475, in which a nonwoven fabric is impregnated with a resin having rubber elasticity and solidified.
Japanese Patent Laid-Open Publication No. Sho 63-152483 further discloses a method of slicing at the intermediate layer, mixing gelatin into a rubber-based material, heating and foaming, and removing a part of the surface skin layer of the molded product. And a method of removing the gelatin on the surface with hot water to make the surface porous.

[0003]

However, the above-mentioned polyurethane resin having a hydroxyl group in a molecule, a liquid rubber having a hydroxyl group in a molecule, an inorganic or organic filler, and a coating film containing an isocyanate prepolymer are blended. In the method of coating the sheet surface with the composition, the surface to be coated is not a surface in which fibers and resins are mixed, and thus the obtained sheet-like material has low moisture permeability, and delicate handling when used for balls, gloves, etc. I can not get the nature. Further, the obtained non-slip property is not satisfactory. Further, in the above-mentioned method of impregnating and solidifying a nonwoven fabric with a resin that cures rubber elasticity and slicing the resin in the intermediate layer, the fiber nap is present on the surface, and the effect of the impregnated resin is not sufficiently exhibited. Further, in the case of the above-mentioned method in which a part of the surface skin layer of a molded article formed by heating and foaming a rubber-based material by mixing gelatin is removed, and the gelatin on the surface is removed with hot water to make the surface porous. However, since the base layer was porous, the mechanical strength was insufficient, and it was not suitable for hard use such as balls and gloves.

[0004] Balls used in events such as American football and basketball are required to have a non-slip property, and are also required to be less slippery even when hands handling such balls are wet by sweat or the like. Also, golf gloves and baseball gloves are required to be less likely to slip due to sweat. An object of the present invention is to provide a leather-like sheet that is excellent in non-slip properties, has hygroscopicity, is excellent in handling properties, and has sufficient mechanical strength.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a leather-like sheet comprising a substrate layer and a raised surface formed on the surface thereof, and having a hole communicating with the interior of the substrate layer. This is achieved by a leather-like sheet characterized in that a resin imparting non-slip properties is applied discontinuously.

[0006] The base layer used in the present invention is a fiber cloth having naps on at least one side and an elastic polymer impregnated therein, irrespective of a knitted or woven cloth, and The leather-like sheet is not particularly limited as long as it has a good thickness and texture. Of course, a knitted fabric and a nonwoven fabric may be overlapped. In particular, in the present invention, a three-dimensional entangled nonwoven fabric is preferable in order to achieve natural leather-like stretchability, texture, napped properties, and the like. In the leather-like sheet of the present invention, since the base layer is made of the fiber fabric and the elastic polymer impregnated therein as described above, the mechanical strength is enhanced by the reinforcing effect of the fiber as compared with the conventional one described above. It is extremely excellent in point. Furthermore, it is extremely important that a fiber fabric is used from the viewpoint of obtaining a natural leather-like performance.

The fibers constituting the woven or nonwoven fabric are not particularly limited, and synthetic fibers such as known cellulose fibers, acrylic fibers, polyester fibers, polyamide fibers, polyolefin fibers, and polyimide fibers are known. Alternatively, natural fibers, regenerated fibers, semi-synthetic fibers and the like may be mentioned, and these fibers may be used alone or in combination of two or more. In order to have good non-slip properties and handling properties, and also to have a natural leather-like flexibility, texture, and feel, the single denier of the surface nap fibers is preferably 0.2 denier or less. Particularly in the present invention,
As the fibers constituting the base layer, the so-called ultrafine fiber bundle in which the fineness of 0.2 denier or less converges several to several hundreds of fibers and the total denier becomes 0.5 to 20 deniers is used. It is preferable in terms of properties and piloerection. Such an ultrafine fiber bundle has a cross section of sea-island by mixing and melting two or more types of incompatible polymers and discharging them from a die, or by melting the polymers separately and discharging them with a spinneret. It is obtained by producing a fiber having a structure or a multi-layer laminated structure, and removing sea components from the fiber, or peeling off between layers.

As described above, in the leather-like sheet constituting the present invention, there are countless fine holes (ie, spaces) communicating with the inside of the base layer, which are present on the surface of the base layer, that is, near or between the roots of the nap. By doing so, it becomes a soft texture comparable to natural leather. Also, the fine communication holes on the surface are
It has a function of absorbing sweat, water, and the like, which are factors that lower the non-slip property, into the inside of the base layer by capillary action, thereby preventing the non-slip property from being reduced by water.

As a method for obtaining a base layer having communication holes, a method of impregnating a woven or nonwoven fabric with a resin solution or dispersion of an elastic polymer and wet coagulating the resin with a non-solvent or destroying the emulsion by heat is used. And coagulation,
A method of adding an easily extractable component to the resin liquid at the time of impregnating the resin and extracting and removing the easily extractable component after coagulation of the resin is exemplified. From the viewpoint of texture and mechanical properties, a method of impregnating a resin solution into a nonwoven fabric entangled with the ultrafine fiber bundle and wet-solidifying the resin is preferable.

As the resin constituting the base layer, a known polymer elastic body can be used, but it is preferable to use a polyurethane resin from the viewpoint of texture. Preferred polyurethane resins are soft segments selected from the group consisting of polyester diols, polylactone diols, polycarbonate diols, polyether diols, etc. obtained by reacting a diol with a dicarboxylic acid or an ester-forming derivative thereof. Number average molecular weight of 500-5
000 at least one polymer diol,
A so-called segmented polyurethane obtained by reacting this with a diisocyanate and a low molecular weight extender is exemplified. As the diol compound, a compound having 6 to 10 carbon atoms is preferable in terms of durability or leather-like texture. For example, 3-methyl-1,5-pentanediol, 1,6-hexanediol, and 2-methyl- 1, 8
-Octanediol, 1,9-nonanediol, 1,1
0-decanediol and the like. Representative examples of dicarboxylic acids include aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, azelaic acid, and sepatic acid, and aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid.

The number average molecular weight of the polymer diol is 500
If it is less than 10%, it is not preferable because it lacks flexibility and a natural leather-like texture cannot be obtained. When the number average molecular weight of the polymer diol exceeds 5,000, the urethane group concentration decreases, so that it is difficult to obtain a sheet having a balance in flexibility, durability, heat resistance, and hydrolysis resistance. Examples of the low molecular weight extender include low molecular weight compounds having two active hydrogen atoms such as ethylene glycol, propylene glycol, butanediol, hexanediol and ethylenediamine. Examples of the diisocyanate include aromatic, aliphatic, and alicyclic diamines such as 4,4'-dibuphenylmethane diisocyanate, tolylene diisocyanate, phenylene diisocyanate, and xylylene diisocyanate. Can be Add pigments, dyes, coagulation regulators, stabilizers, etc. as necessary
And two or more polymers may be used in combination.

Although there is no particular limitation on the method of applying the resin, a method of impregnating the fibrous sheet with the resin liquid is preferred from the viewpoint of the balance of the hand. In addition, from the viewpoint of natural leather-like soft texture, the weight ratio of the fibers constituting the knitted fabric or nonwoven fabric of the base layer and the polymer elastic body is 30/70 to 7 in weight ratio.
It is preferably in the range of 0/30. More preferably, the weight ratio of fiber / elastic body is 40/60 to 55/45.
Is within the range. If the ratio of the fibers in the base layer is too low, a rubber-like texture is unfavorable, and if the ratio of the fibers is too high, the texture becomes paper-like, and the desired natural leather-like texture cannot be obtained.

[0013] The method of making naps exist on the surface of the substrate layer is not particularly limited, but preferably, a method of rubbing the surface with an abrasive such as sandpaper and excavating the fibers is a high-quality natural leather-like texture. Is preferred. The napped hair is necessary particularly in view of the handleability and the strong adhesion of the surface coating resin to the base layer. In particular, as a surface resin that imparts non-slip properties, an isoprene-based polymer is preferable as described below. In this case, the solubility parameter between the polymer elastic body of the base layer and the surface resin is largely apart, and the Is poor, so the surface resin is easily peeled off. In particular, since the leather-like sheet of the present invention is suitably used for products that are subjected to extremely intense force, such as various balls and gloves, the surface resin is required to have high peel resistance. In order to meet this requirement, it is particularly important that surface naps are present. If the surface is not raised, the surface resin applied to the base layer tends to peel off, which is not preferable.

Further, in order to enhance the adhesiveness, a method in which a prepolymer or the like is applied to the entire surface of the naps and the surface resin is formed with an adhesive layer interposed therebetween is not preferable because the effect of the communication holes is reduced. As the resin that imparts non-slip properties, solvent-type polymers and emulsion-type polymers such as resins obtained by polymerizing rubber monomers such as butadiene and isoprene, and acrylic polymers obtained by polymerizing acrylic monomers are preferable, and they also impart their non-slip properties. Other types of polymers may be combined with the resin. Further, the above-mentioned monomer and another monomer may be subjected to block copolymerization. Known tackifiers such as polyterpene resins and petroleum hydrocarbon resins may be added to the resin applied to the surface. Particularly preferred is a styrene-isoprene copolymer obtained by block copolymerization of polystyrene and polyisoprene, or a polymer obtained by hydrogenating at least a part thereof. The effect of improving the shape retention of the molded base layer is also obtained. It is also possible to adjust the non-slip property by adding inorganic or organic particles or powder.

When the leather-like sheet of the present invention is used for a ball or the like, in order to further improve the anti-slip effect, the surface of the base layer is undulated before the surface resin is applied. Is preferable. Also softener,
Fillers, antioxidants and the like may be added to the surface resin as long as the friction resistance of the surface is not reduced. As a method of applying a resin that imparts non-slip properties, a method of applying in a discontinuous state is used. As a specific method, a method in which a gravure roll is used to transfer dots in a mesh shape while having non-transferred points in a mesh shape. Similar effects can be obtained by application by a spray method or the like. On the other hand, a method of coating the entire surface with a certain thickness, such as a knife coat, a method of applying a resin to the entire surface of a base material, such as process paper, forming a film, and bonding it to the base layer via an adhesive layer, and a method of extruding There are methods such as uniformly extruding onto a substrate layer through a die to form a film on the surface.In these methods, however, since the resin layer is usually applied to the surface of the substrate layer in a continuous state, the resin layer is mixed and integrated with the nap fibers. However, it is not preferable because the delicate handling property obtained by the conversion cannot be obtained, and the effect of absorbing moisture adhering to the surface by the communication holes into the inside of the base layer cannot be obtained.

The term "non-continuous" as used in the present invention refers to a state in which the resin is not applied to the entire surface of the raised hair. The resin layer exists continuously in a certain direction, but the resin layer exists in a certain direction. This means a state where the layer is discontinuous and a state where the resin layer is discontinuous in all directions. In the present invention, when a leather-like sheet having an arbitrary size of 1 cm square is cut out, a resin layer in which a portion where a resin layer is present and a portion where no resin is present always coexist on a napped surface. Is preferred.

As a method of measuring the non-slip property of a leather-like sheet, a method of measuring the surface friction coefficient with a friction tester KES-SE manufactured by Kato Tech Co., Ltd. at a temperature of 20 ° C. and a humidity of 65% can be mentioned. When the non-slip property of the leather-like sheet was measured using this method, it was found that when the surface friction coefficient was in the range of 0.5 to 10, the handling property was good and an excellent anti-slip effect was obtained. I found it. Further, also in the leather-like sheet of the present invention, it is preferable that this condition is satisfied. In particular, the styrene-isoprene copolymer obtained by block copolymerization of polystyrene and polyisoprene, or a hydrogenated product thereof is preferably used. When used as a resin and these resins are present in a discontinuous state, a surface friction coefficient of 0.5 to 10 is satisfied due to a synergistic effect between these resins and the raised surface. When the surface friction coefficient is higher than 10, the non-slip property is too high, and the surface touch becomes a sticky touch, and there is a problem in handling properties and workability as products such as balls and gloves. If the surface friction coefficient is lower than 0.5, the desired non-slip property is low and the handling property is poor. In the present invention, as a resin that imparts non-slip properties, a resin whose value measured by the tester is 0.5 to 10 when the resin is entirely coated on a polyester film so as to have a thickness of 50 μm. This means that when an additive is present in the resin, the measurement is performed in a state where such an additive is contained. Therefore, even if the resin alone does not satisfy the above-mentioned surface friction coefficient, the addition of the additive may satisfy the above-mentioned surface friction coefficient in some cases.

[0018]

EXAMPLES Next, the embodiments of the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. The parts and percentages in the examples are based on weight unless otherwise specified. The measurement method of the coefficient of surface friction is the friction tester KES- manufactured by Kato Tech Co., Ltd.
The measurement was carried out in SE at a temperature of 20 ° C. and a humidity of 65%.

Example 1 Nylon and polyethylene were mixed in a chip at a ratio of 50/50 and spun by an extruder to spin sea-island fibers (nylon is an island component and polyethylene was a sea component).
The 4-denier cut short fibers were entangled to obtain a nonwoven fabric. The fibrous sheet is impregnated with a dimethylformamide solution of polyurethane (polyurethane composed of polyethylpentane adipate and polyethylene glycol having an average molecular weight of 2,000, and composed of 4,4'-diphenylmethane diisocyanate and butanediol), and wet coagulated. Extract the sea component of the fiber, the basis weight 270 g / m ² , the thickness 0.8 mm, polyurethane and fiber
A base layer having a ratio of fiber to 55/45 was obtained. The fineness of the nylon ultrafine fibers of the obtained sheet was 0.06 denier on average, and had a soft leather-like texture. One surface of the obtained base layer was buffed with sandpaper to obtain a raised surface made of the nylon ultrafine fibers. Basketball-like embossed irregularities were imparted to the surface with an embossing machine to enhance non-slip properties.

As the resin for improving the non-slip property, a hydrogenated product of styrene-isoprene block copolymer (SEPS) [Septon 2043 manufactured by Kuraray Co., Ltd .: surface friction coefficient of 0.8 according to the measuring method for the 50 μm-thick layer]
A solution prepared by dissolving 30 parts in 100 parts of toluene was prepared, and applied to the napped surface of the base layer at a coating amount of 30 g / m ² by a gravure method. Observation of the coated surface reveals that the resin layer has an average diameter of 0.1 mm.
A 13 mm round size was applied in the form of a spot and an uncoated portion having a width of about 0.03 mm was present between adjacent spots. When this leather-like sheet is observed on a cut surface in the thickness direction by an electron microscope,
It was found that there were countless holes extending from the surface of the base layer to the inside and further to the back. The moisture permeability of the obtained product is 25
Was 60g / m ^2/24 hours, was measured to measure the non-slip properties at Kato Tech Co., Ltd. Friction Tester KES-SE, the surface friction coefficient μ was 3.0.
Further, when processed into gloves and subjected to a practical test, the surface tackiness was good, and even when wet, it became slightly slippery, but the effect of anti-slip was not lost. When this leather-like sheet was used as a surface material of a basketball, it was excellent in non-slip property and easy to handle. Further, even after use for 3 months, the surface resin was hardly peeled off, and there was no decrease in non-slip property. Furthermore, it was also excellent in mechanical performance such as tensile strength.

Example 2 The same method as in Example 1 was adopted except that the fiber layer of Example 1 was replaced with a woven cloth having a denier of 2.0 denier and the extraction step and the embossing step were not performed. As a result of the treatment, a sheet which could be said to be a leather-like sheet was obtained although it was considerably inferior to that of Example 1 in flexibility, texture, appearance and the like. The weight ratio between the fibers and the elastic polymer in this sheet was 65/35. When the leather-like sheet was observed with an electron microscope in the same manner as in Example 1, it was found that, as in Example 1, there were countless holes extending from the surface of the base layer to the inside and further to the back. When this leather-like sheet was processed into gloves and balls for American football, it was excellent in non-slip properties although it was slightly inferior to that of Example 1.

Example 3 In the process of Example 1 described above, in order to further increase the frictional properties of the resin for improving the non-slip property, a tackifier (polyterpene resin) was added at 50% to the resin to carry out the treatment. However, a leather-like sheet having a good surface tackiness and an excellent texture was obtained. When this leather-like sheet was used for gloves and basketball balls, it showed a better non-slip property than that of Example 1.

Comparative Example 1 In Example 1, a vinyl acetate resin was used instead of the hydrogenated product of the styrene-isoprene copolymer (the surface friction coefficient was 0.5
5) was extruded onto the substrate layer of Example 1 at 25 g / m ²
Was applied over the entire surface to obtain a sheet having some non-slip properties. However, in a practical test, there was no moisture permeability, so it slipped when sweating, and was not a satisfactory function with surface touch.

Comparative Example 2 In Example 2, a vinyl acetate resin was used in place of the hydrogenated styrene-isoprene copolymer.
This was extruded on a wrinkle-type release paper to obtain a second embodiment.
When the substrate was laminated on the entire surface of the base layer at a coating amount of 15 g / m ^2, a leather-like sheet having almost no moisture permeability was obtained. In addition, the non-slip property was slightly lacking, and it could not be said that the non-slip property was not only in a practical test but also in a non-sweating state.

The performance of the leather-like sheet obtained by the above Examples and Comparative Examples is shown in Table 1 below.

[0026]

[Table 1] In the above table, ◎ indicates extremely good, ○ indicates good, Δ indicates poor, and × indicates extremely poor.

[0027]

According to the present invention, a leather-like sheet having excellent non-slip properties, excellent handling properties, and sufficient mechanical strength can be obtained even when wet as well as when dry. The leather-like sheet of the present invention is particularly suitable for sports gloves requiring non-slip properties and mechanical strength, balls for American football and basketball, and the like.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) D06N 3/00-3/18

Claims (5)

(57) [Claims] 1. A leather-like sheet comprising a base layer and a raised surface formed on the surface thereof, and having a hole communicating with the inside on the surface of the base layer, wherein the raised surface has a non-slip property. A leather-like sheet, wherein the applied resin is applied in a discontinuous manner. 2. The leather-like sheet according to claim 1, wherein the resin imparting non-slip properties is a styrene-isoprene block copolymer or a hydrogenated product thereof. 3. The leather-like sheet according to claim 1, wherein the surface on which the resin is applied is shaped. 4. A glove comprising the leather-like sheet according to claim 1. 5. A ball comprising the leather-like sheet according to claim 1.