JP3127129B2 - Microporous sheet, substrate for artificial leather, and method for producing them - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microporous sheet, particularly a substrate for artificial leather, and a method for producing the same. More specifically, it is a microporous sheet made by impregnating a non-woven fabric with an elastic polymer, and easily and properly adjusts properties such as flexibility, abrasion resistance, tensile strength and tear strength according to the purpose and application. And a method for producing the same. The microporous sheet of the present invention can be advantageously used as a base for artificial leather.

[0002] Substrates for artificial leather, which can be coated with a high molecular polymer to form artificial leather with silver, or whose surface is ground to form artificial leather of suede or nubuck tone, include: Conventionally, a base fabric made of a woven fabric, a knitted fabric, or a nonwoven fabric is generally impregnated with a high-molecular polymer, and in particular, an elastic polymer such as polyurethane is used as the base fabric of the nonwoven fabric because of its strength and durability. Is generally used. However, in producing a microporous sheet material suitable for these artificial leather substrates, a fiber base cloth such as a nonwoven fabric is simply impregnated with an organic polar solvent solution such as dimethylformamide of an elastic polymer, and then subjected to water immersion coagulation. If you just do it, the elastic polymer will bond the fibers,
Although features such as difficulty in elongation and abrasion resistance are obtained, the material becomes hard and the range of use as a natural leather substitute is narrow, and its use is limited. Therefore, various measures have been taken in the art to prevent the elastic polymer from adhering to the fibers. For example, JP-A-47-9839 (U.S. Pat.
No. 923), there is a method in which a treatment agent such as silicone having a releasing effect on the elastic polymer is applied to the fiber surface before impregnation before impregnation. In this method, when the medium of the impregnating liquid is water, the adhesion between the elastic polymer and the fibers is hindered, giving the fibers a large degree of freedom to obtain a microporous sheet suitable for a flexible artificial leather substrate. Can be. However, when the medium is an organic polar solvent such as dimethylformamide, the effect is small and a flexible sheet cannot be obtained. Further, when the fibers are covered with a treating agent having a releasing effect such as silicone, the elastic polymer does not adhere to the fibers as described above, so that flexibility is obtained, but the coefficient of friction between the fibers is reduced and the fibers are easily stretched. In addition, disadvantages such as reduced wear resistance are also increased.

Further, as a method for producing a microporous sheet in which fibers are not adhered to an elastic polymer, for example, Japanese Patent Publication No. Sho 48
As described in JP-A-31955, a water-soluble polymer such as polyvinyl alcohol and an insoluble in dimethylformamide are previously applied to the fiber surface, impregnated with a dimethylformamide solution of polyurethane, and then subjected to water immersion coagulation. After that, there is a method of washing and removing the polyvinyl alcohol with water. According to this method, adhesion between the polyurethane and the fiber is prevented, and the fiber has a large degree of freedom, so that a soft artificial leather substrate can be obtained. However, in this case, flexibility is obtained, but disadvantages such as easy elongation and reduced wear resistance also occur. That is, if the polyurethane and the fiber are completely bonded, there are advantages such as excellent abrasion resistance and difficulty in elongation, but disadvantages such as hardness and a decrease in tear strength occur, and conversely, the polyurethane and the fiber are completely bonded. If not, flexibility is obtained, but disadvantages such as reduced wear resistance and easy elongation occur.

[0004]

In recent years, artificial leather has been used in shoes,
It is widely used for applications such as balls, furniture, clothing, gloves, and other miscellaneous goods, and the required properties are different depending on these applications and types of processing methods. Therefore, the prior art has reached its limit in responding finely to a wide range of applications and processing methods. Therefore, the present inventor can arbitrarily control the state of the bonded portion and the non-bonded portion (the bonded portion and the non-bonded portion) of the fiber and the elastic polymer in the nonwoven fabric, and the type of the application and the processing method is limited. Correspondingly, research was conducted to provide a microporous sheet material suitable for an artificial leather substrate capable of easily changing this state (density and ratio of adhesion and non-adhesion) and a method for producing the same. Advanced.

As a result, a specific surfactant is dissolved in a solution of an elastic polymer, the solution is impregnated into a nonwoven fabric, and solidified in water. And fibers were found to be in a bonded state and a non-bonded state. Thus, the present inventors constructed a nonwoven fabric from at least two types of fibers, changed the proportion of the types of the fibers, and impregnated an elastic polymer solution containing a specific surfactant to form an elastic polymer and fibers. Found that the bonded portion and the non-bonded portion can be arbitrarily controlled, and the flexibility, abrasion resistance and strength can be balanced and arbitrarily controlled, and the present invention has been achieved.

[0006]

According to the present invention, there is provided a microporous sheet obtained by impregnating and solidifying an elastic polymer in a nonwoven fabric, wherein (1) the nonwoven fabric comprises: (2) The microporous sheet material is obtained by mixing (i) the elasticity of the fiber A with the elasticity of the polyester fiber (fiber A) and (b) the polyolefin fiber or the polyamide fiber (fiber B). The portion bonded and surrounded by the polymer and the portion where the fiber B is surrounded by the elastic polymer in a non-bonded state are scattered, (ii) the flexibility is 0.5 to 6.0, and (ii)
i) A microporous sheet having a wear resistance of 1500 to 8000 is provided.

Further, according to the present invention, a nonwoven fabric is impregnated with an organic polar solvent solution of an elastic polymer, and then the solution is coagulated in a coagulation bath mainly composed of water to produce a microporous sheet. In the method, (1) a non-woven fabric mixed with polyester fiber (fiber A) and polyolefin fiber or nylon fiber (fiber B) is used as the non-woven fabric, and (2) the organic polar solution is contained therein. A fine solution characterized by using a solution in which 0.1 to 10 parts by weight of a surfactant which is water-dispersible or water-soluble and has a silicone segment as a hydrophobic group per 100 parts by weight of the elastic polymer is dissolved. A method for producing a porous sheet is provided.

Hereinafter, the microporous sheet-like material of the present invention and a method for producing the same will be described in detail. The fibers constituting the nonwoven fabric fabric of the present invention are a mixture of two types of fibers A and B. Fiber A is an aromatic polyester fiber, and fiber B is a polyolefin fiber or a polyamide fiber. In the following description, “a surfactant that is water-dispersible or water-soluble and has a silicone segment as a hydrophobic group” contained and mixed in an organic polar solvent solution is simply referred to as a “silicone-based surfactant”. May be abbreviated.

The fiber A adheres to the type A fiber when the elastic polymer coagulates in a coagulation bath, regardless of the presence or absence of the silicone surfactant dissolved in the impregnating liquid. Aromatic polyester fibers are typical ones that have surface properties that give a condition. Specific examples of the aromatic polyester include, for example, polyethylene terephthalate, polybutylene terephthalate, polyhexamethylene terephthalate, polyethylene isophthalate, polyethylene-2,6-naphthalate, and copolymers thereof. Fiber A is different from fiber B, and despite the presence of the silicone-based surfactant mixed in the impregnating liquid, these fibers A and the impregnated elastic polymer are in a state of adhesion (referred to as "adhesion"). Although it is not clear about the mechanism that brings about, it is presumed as follows. When the organic polar solvent solution of the elastic polymer impregnated in the vicinity of these fibers A is immersed in a coagulation bath solution mainly composed of water, the organic polar solvent as a solvent is eluted into the coagulation bath solution and the elastic polymer solution Coagulates, at which time the silicone surfactant coordinates to the elastic polymer surface. The surface of the elastic polymer is made water-repellent by the polysiloxane segment, which is a hydrophobic group of the coordinated silicone surfactant, but since the fiber A has a strong affinity for the polysiloxane, the adhesion between the elastic polymer and the fiber A It is thought to cause a condition. As the fiber A, a fiber of polyethylene terephthalate or a copolymer containing at least 80 mol%, preferably at least 85 mol% of ethylene terephthalate units in all repeating units is preferable.

[0010] The fiber B constituting the nonwoven fabric fabric of the present invention is formed by the effect of the silicone surfactant dissolved in the impregnating liquid when the elastic polymer is coagulated in the coagulation bath. It has surface properties that result in a non-bonded state with B, so that the fiber B is surrounded by the elastic polymer in a non-bonded state. The polymer forming the fiber B is, for example, polyolefin such as polypropylene or polyethylene and 6 nylon, 6/6 nylon, 6 /
Examples thereof include aliphatic polyamides such as 10 nylon, 10/9 nylon, 10/10 nylon, 11 nylon, and 12 nylon. The mechanism by which these fibers B and the impregnated elastic polymer cause a state of non-adhesion (referred to as “non-adhesion”) in the presence of the silicone-based surfactant mixed in the impregnation liquid is not clear. It is estimated as follows. When the organic polar solvent solution of the elastic polymer impregnated in the vicinity of these fibers B is immersed in a coagulation bath solution mainly composed of water, the organic polar solvent as a solvent is eluted into the coagulation bath solution and the elastic polymer is dissolved. Coagulates, at which time the silicone surfactant coordinates to the elastic polymer surface. The surface of the elastic polymer becomes water-repellent due to the polysiloxane segment which is a hydrophobic group of the coordinated silicone-based surfactant, and the contact with the fiber B is hindered via a water / organic polar solvent mixture present between the elastic polymer surface and the fiber B. It is considered that a non-adhesion state is caused by the application.

The polymer forming the fiber B is preferably polypropylene or polyethylene in the case of polyolefin, and 6 nylon or 6/6 in the case of nylon.
Nylon is preferred. As the fiber B, these polyolefin fibers are particularly preferable.

In the present invention, when a nonwoven fabric comprising a fiber A and a fiber B is impregnated with an organic polar solvent solution of an elastic polymer containing a silicone-based surfactant and subjected to water immersion coagulation, the fiber B portion becomes The microporous sheet has a structure in which the non-adhered state is formed with the elastic polymer, while the portion of the fiber A forms the bonded state with the elastic polymer, that is, the non-adhered state and the bonded state of the fiber and the elastic polymer coexist randomly. It becomes a state thing. In general, a microporous sheet having a non-adhesive structure gives a great degree of freedom to fibers, and thus has high flexibility. However, it tends to be easily stretched and has reduced abrasion resistance. The sheet-like material is difficult to stretch because the fiber has no flexibility, and has high abrasion resistance, but is very hard. Thus, in the present invention, by adjusting the mixing ratio of the fiber A and the fiber B, it is possible to arbitrarily adjust the ratio of the non-adhesive structure and the adhesive structure between the elastic polymer and the fiber. The balance of properties such as abrasion resistance can be widely selected as needed. In the present invention,
The mixing ratio of fiber A and fiber B can be arbitrarily selected, but a nonwoven fabric obtained by mixing fiber A: fiber B at a weight ratio of 70:30 to 5:95 is preferable from the viewpoint of flexibility. The ratio of fiber A: fiber B is 60:40 to 1 by weight.
A range of 0:90 is particularly preferred.

The form of the nonwoven fabric of the present invention is not limited as long as the fibers constituting the nonwoven fabric are a blend of fibers A and B, but the fibers A and B are uniformly blended throughout. Is desirable. By impregnating an elastic polymer into a nonwoven base fabric in which fibers A and B are uniformly mixed, (a) a portion where fiber A is bonded and surrounded by the elastic polymer, and (b) fiber B is in a non-adhered state by the elastic polymer. To obtain a microporous sheet-like material in which two types of portions surrounded by are present in a uniformly dispersed state.

As specific examples of the form of the nonwoven fabric base fabric of the present invention, (i) short fibers are uniformly spread by a spreader typified by a carding process and then laminated to form a spread web; Or a fiber entangled fiber that has been subjected to fiber entanglement by contact with a high-speed liquid flow; (ii) a fiber entangled fiber that has been subjected to fiber entanglement by laminating a long-fiber nonwoven fabric and the spread fiber; A web and a fiber entanglement treatment; (iv) a wet-laid nonwoven fabric and the spread fiber web and a fiber entanglement treatment; and (v) a long-fiber nonwoven fabric of two or more types. Laminated and subjected to a fiber entanglement treatment, (vi) a splittable fiber in which polymers of fiber A and fiber B are alternately arranged is formed as the spread web, and is contacted with a needle punch or a high-speed fluid. Those subjected to a fiber entanglement treatment are exemplified.

The form of these nonwoven fabric base fabrics may be formed by mixing two kinds of fibers, or may be formed by laminating two or more kinds of fiber layers. In any case, it is preferable to appropriately combine a cotton mixing means, a laminating means or a fiber entanglement means so as to form a nonwoven fabric in a form in which the fibers A and B are homogeneously mixed. As the form of the nonwoven fabric, a fabric obtained by mixing the two types of short fibers (i) among the above to form an open fiber web and performing a fiber entanglement treatment is suitable as a sheet for artificial leather.

Fiber A and Fiber B Constituting Nonwoven Fabric Base Fabric
May be long fibers or short fibers. However, either one or both are preferably short fibers, and particularly preferably both are short fibers. When either one is a long fiber, the fiber A is preferably a long fiber. The fineness of the fiber A is suitably in the range of 0.05 to 100 de, preferably 0.1 to 5.0 de.
Has a fineness of 0.05 to 100 de, preferably 0.1 to 5.
A range of 0 de is appropriate. In the case of short fibers, the fiber length depends on the form of the nonwoven fabric, but is generally 20 to 20.
0 mm, preferably in the range of 30 to 80 mm. In this case, not only isometric cuts but also bias cuts are included.

The elastic polymer in the present invention may be an elastic polymer usually used for a base fabric for artificial leather.
Preferably, it is polyurethane. As such a polyurethane, those used as a base fabric for artificial leather are suitable, and are conventionally known thermoplastic polyurethanes obtained by a polymerization reaction of an organic diisocyanate, a polymer diol and a chain extender. The organic diisocyanate used here is an aliphatic, alicyclic or aromatic diisocyanate containing two isocyanate groups in the molecule, especially 4,4 ′
-Diphenylmethane diisocyanate, P-phenylene diisocyanate, toluylene diisocyanate, 1,
5-naphthalene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and the like. As the polymer diol, for example, at least polyester glycol obtained by condensation polymerization of glycol and aliphatic dicarboxylic acid, polylactone glycol obtained by ring-opening polymerization of lactone, aliphatic or aromatic polycarbonate glycol, or polyether glycol Polymer glycols having an average molecular weight of 500 to 4000 selected from one type. As the chain extender, a diol having a molecular weight of 500 or less containing two hydrogen atoms capable of reacting with isocyanate, for example, ethylene glycol, 1,4-butanediol, hexamethylene glycol, xylylene glycol, cyclohexanediol, neopentyl glycol, etc. No.

The elastic polymer, especially polyurethane, is used as a solution (concentration: 6 to 20% by weight) dissolved in an organic polar solvent. A microporous sheet is formed by a method of impregnating the nonwoven fabric with this solution, that is, a wet method. A microporous sheet is formed by impregnating the nonwoven fabric with the solution and then extracting the organic polar solvent in a coagulation bath mainly composed of water, thereby coagulating the elastic polymer.

The organic polar solvent used to dissolve the elastic polymer includes, for example, dimethylformamide, diethylformamide, dimethylacetamide, dimethylsulfonamide, tetrahydrofuran and dioxane, of which dimethylformamide is preferred.

In order to obtain the object of the present invention, a microporous sheet material is prepared by dispersing an elastic polymer in an organic polar solvent solution on a nonwoven fabric, and dispersing or dispersing in water or water. A solution in which a surfactant having a silicone segment as a base (silicone surfactant) is added and mixed is used. This silicone-based surfactant preferably contains 10 to 90% by weight of a silicone segment. The silicone surfactant preferably has a polysiloxane unit as a hydrophobic group in the molecule and a unit mainly containing a polyoxyalkylene chain as hydrophilic. Alternatively, it can be obtained by a method in which an alkylene oxide such as ethylene oxide is added as a hydrophilic group to a polysiloxane having a group that reacts with an alkylene oxide such as ethylene oxide in the molecule. Alternatively, it can be obtained by reacting an organic polyvalent isocyanate with a polysiloxane having a group that reacts with isocyanate at the molecular end or in the molecule, and then reacting with a polyoxyalkylene glycol mainly composed of polyoxyethylene glycol.

The silicone-based surfactant of the present invention is suitably one which is substantially formed of a silicone segment and a polyalkylene oxide segment, particularly 10 to 90% by weight, particularly preferably 20 to 90% by weight of the silicone segment. Those containing 80% by weight are advantageous. As the polyalkylene oxide, polyethylene oxide, polypropylene oxide, polybutylene oxide or a copolymer thereof is preferable, and particularly, polyethylene oxide or a compound mainly containing polyethylene oxide is preferable.

The silicone surfactant preferably has a molecular weight in the range of 1200 to 120,000, and the polysiloxane component in the molecule preferably has a molecular weight of 400 to 25,000. When the molecular weight of the polysiloxane component is less than 400 or the molecular weight of the silicone-based surfactant is 12
If it is less than 00, the silicone surfactant is easily leached out of the coagulated elastic polymer, and if the molecular weight of the surfactant exceeds 120,000, the fiber of the present invention is used in an amount which does not decrease the physical properties of the elastic polymer. It becomes difficult to form a non-adhesive structure of B and the elastic polymer or to dissolve the polar polymer in the polar solvent.

In the present invention, the amount of the silicone surfactant added to the organic polar solvent solution of the elastic polymer is from 0.1 part to 100 parts by weight of the solid of the elastic polymer.
10 parts, preferably 0.5 to 3.0 parts. If the addition amount of the silicone surfactant is less than 0.1 part, it will be difficult to form a non-adhesive structure of the fiber B and the elastic polymer of the present invention, which will be described later, during water immersion coagulation. When the amount of the silicone surfactant added is 10
If it exceeds the part, the silicone-based surfactant becomes easy to leach out of the coagulated elastic polymer, which is not preferable because it causes trouble during post-processing when making artificial leather, and when processing with products such as shoes and balls. .

The microporous sheet material of the present invention thus obtained has excellent properties as a base cloth for artificial leather, and the properties can be controlled arbitrarily widely. Among its properties, the degree of flexibility is 0.5 to 6.0, preferably 0.6 to 6.0.
5.0, more preferably 0.7 to 3.0, and the abrasion resistance is 1500 to 8000, preferably 1500 to 8000.
The range is 5000. Preferably, the microporous sheet of the present invention has a 20% elongation stress of 1.0 to 8.0.
It has a value of 0, preferably 2.0-6.0, and a tear strength of 3-8, preferably 4-7. The apparent specific gravity of the microporous sheet of the present invention is 0.2 to 6.6.
0 g / cm ^3, preferably in the range of 0.3 to 5.0 g / cm ^3, and has a relatively light tender texture.

As described above, the microporous sheet material of the present invention has both appropriate flexibility and abrasion resistance in a well-balanced manner. This is considered to be because a difference was caused in the state in which the fibers were surrounded by the elastic polymer based on the difference in the types of the fibers when the base fabric was used. That is, fiber A is generally adhesively (or bonded) surrounded by an elastic polymer, while fiber A is generally non-adhered (or non-bonded) surrounded by an elastic polymer, and the latter is a method in which fiber B It is considered that the above characteristics are exhibited by having more degrees of freedom.

In the microporous sheet-like material of the present invention, a portion where fibers are bonded and surrounded by an elastic polymer and a portion where fibers are not surrounded are scattered, and the ratio can be arbitrarily controlled. It is possible to obtain a product having a wide flexibility and other physical properties. Whether the fibers are surrounded by the elastic polymer by adhesion or non-adhesion can be easily determined by observing a photograph of the cross section of the microporous sheet material by an electron microscope. The state of non-adhesion (or non-bonding) can be said to be a state in which the fiber is surrounded by the elastic polymer via the interfacial gap, and can be observed by the above photograph. On the other hand, the state of being bonded and surrounded refers to a state in which there is no interface void between the fiber and the elastic polymer.

The microporous sheet of the present invention can be used for various applications as it is. For example, the fabric itself can be used as a base fabric for artificial leather, but by forming an elastic polymer layer on one or both surfaces thereof, a more substantial base fabric for artificial leather can be obtained. This elastic polymer layer is formed by applying a solution of the above-mentioned elastic polymer (this solution does not necessarily need to contain a silicone-based surfactant) to the surface of the obtained microporous sheet. It may be applied and dried or wet coagulated and dried, or laminated using release paper. The thickness of the elastic polymer layer on the surface is usually in the range of 20 to 500 μm, preferably 30 to 300 μm.

[0028]

Hereinafter, the present invention will be described in detail with reference to Examples. In the examples, “parts” and “%” are based on weight, and the characteristic measured values are obtained by the following methods.

A. A test piece having a flexibility of 25 mm × 90 mm was prepared, and the lower 20 mm in the longitudinal direction was held vertically by a holder, and 20 mm from the holder.
The holder is slid and fixed while bending the sample so that the center of the U-gauge measuring section at the height of 20 mm is 20 mm from the tip of the other end of the test piece. After 5 minutes from the start, the stress was read from a recorder, converted into stress per 1 cm width, and expressed in g / cm as the degree of flexibility (bending resistance). B. Elongation characteristics The stress at the time of 20% elongation is measured by a method according to the method of JIS-K6550, and expressed as Kg / cm as the 20% elongation stress when converted per width of 1 cm (this measurement method is ASTM
D2209). C. Abrasion resistance Abrasion resistance is measured by the method according to JIS-L1096 C method (Taber-type method), the wear wheel is H22, and the abrasion resistance is expressed by the number of times until all the layers are worn. ASTM
D4060). D. Tear Strength The tear strength is measured by a method according to the measurement of the tear strength of JIS-K6550, and the unit is expressed in Kg (this measurement method is ASTM D
4704).

Example 1 30% polyethylene terephthalate fiber (2.0 denier, cut length 51 mm, number of crimps 13 / 25.4 mm)
And polypropylene fiber (2.0 denier, cut length 50)
mm, number of crimp 13 / 25.4mm) 70%,
Create a laminated web using cards and cross layers,
Needle room equipped with 40th needle with regular barb, depth 7mm, density 700 / c
subjected to punching m ^2, and obtained the entangled web. Then
Pressing with a mirror-finished metal roll with a surface temperature of 130 ° C, the thickness is 1.
Non-woven fabric-1 having a thickness of 0 mm and a basis weight of 230 g / m ² was obtained.

On the other hand, 4,4'-diphenylmethane diisocyanate, polytetramethylene glycol having a molecular weight of 2,000, polybutylene adipate having a terminal diol molecular weight of 1700, and diethylene glycol were polymerized in a dimethylformamide solution to give a 12% polyurethane. -A dimethylformamide solution in which a silicone oil having ethylene oxide added as a silicone-based additive (trade name: FG-10, manufactured by Matsumoto Yushi Seiyaku Co., Ltd., 56% silicone segment, 46% ethylene oxide segment, average molecular weight) About 4000)
Was added and mixed in an amount corresponding to 1.0 part with respect to 100 parts of polyurethane solid content to prepare impregnation liquid-1. Next, the impregnating liquid-1 is impregnated into the nonwoven fabric-1, and the excess impregnating liquid on the front and back surfaces is scraped off, immersed in an aqueous solution of 10% dimethylformamide to coagulate the polyurethane, washed with water, dried and artificially washed. Substrate-1 for leather was prepared.

The obtained artificial leather substrate-1 was 1.0 m
m, a weight of 405 g / m ² , and the flexibility, elongation properties, abrasion resistance, and tear strength were balanced as artificial leather for shoes as shown in Table 1. As a result of observing the cross-sectional structure with an electron microscope, it was confirmed that a portion where the polyurethane was bonded to the fiber and a portion where the polyurethane was present in a non-bonded state between the fibers were mixed.

Comparative Example 1 Using the nonwoven fabric-1 prepared in Example 1 as the nonwoven fabric, 12 mol of a higher aliphatic alcohol ethylene oxide adduct was added to the 12% polyurethane-dimethylformamide solution obtained by the polymerization reaction in Example 1. (Sanyo Chemical Industries, Ltd.)
Nonipol SDH-90), polyurethane solid content 1
An artificial leather substrate-2 was prepared in the same manner as in Example 1 by adding and mixing an amount equivalent to 1.0 part with respect to 00 parts and preparing and using the impregnating liquid-2. The obtained artificial leather substrate-2 has a thickness of 1.0 mm and a weight of 400 g / m ² ,
It was very hard, and other properties were unbalanced for artificial leather. In addition, as a result of observing the cross-sectional structure with an electron microscope, a portion where the polyurethane was bonded to the fibers could be confirmed, but a portion where the polyurethane was not bonded between the fibers could not be confirmed.

Comparative Example 2 90% polyethylene terephthalate fiber (2.0 denier, cut length 51 mm, number of crimps: 13 / 25.4 mm)
And polypropylene fiber (2.0 denier, cut length 50)
mm, number of crimp 13 / 25.4mm) 10%,
Create a laminated web using cards and cross layers,
Needle room equipped with 40th needle with regular barb, depth 7mm, density 700 / c
subjected to punching m ^2, and obtained the entangled web. Then
Pressing with a mirror-finished metal roll with a surface temperature of 130 ° C, the thickness is 1.
0 mm, to obtain a nonwoven fabric -2 basis weight 230 g / m ^2.

The obtained non-woven fabric 2 was impregnated with the impregnating liquid -1 mixed with the silicone-based additive prepared in Example 1, and then the substrate 3 for artificial leather was prepared in the same manner as in Example 1. Created. The obtained artificial leather substrate-3 had a thickness of 1.0 mm, a weight of 405 g / m ² , was very hard, and had other characteristics unbalanced as artificial leather. . In addition, as a result of observing the cross-sectional structure with an electron microscope, a portion where the polyurethane was bonded to the fiber was confirmed, but a portion where the polyurethane was in a non-bonded state between the fibers was almost scattered, and was hardly confirmed.

Example 2 Polyethylene terephthalate fiber (2.0 denier, cut length 51 mm, number of crimps 13 / 25.4 mm) was made into a laminated web using a card and a cross layer, and a card and a cross layer were separately formed thereon. Polypropylene fiber (2.0 denier, cut length 5)
0 mm, number of crimps 13 / 25.4 mm) The web was laminated, and punched with a depth of 7 mm and a density of 700 / cm ² in a needle room equipped with a 40th needle having a regular barb to obtain an entangled web. Was. Then, it was pressed with a mirror-finished metal roll having a surface temperature of 130 ° C. to obtain Nonwoven Fabric-3 having a thickness of 1.0 mm and a basis weight of 230 g / m ² . The obtained nonwoven fabric-3 was impregnated with the impregnating liquid-1 mixed with the silicone-based additive prepared in Example 1, and then the same procedure as in Example 1 was carried out to prepare an artificial leather substrate-4.

The obtained artificial leather substrate-4 had a thickness of 1.
It had a weight of 0 mm and a weight of 405 g / m ² , and the flexibility, elongation properties, abrasion resistance and tear strength were balanced as artificial leather for shoes as shown in Table 1. As a result of observing the cross-sectional structure with an electron microscope, it was found that the upper layer with many polypropylene fibers had non-bonded polyurethane between the fibers, and the lower layer with many polyester fibers had polyurethane bonded to the fibers. It could be confirmed.

Example 3 Polyethylene terephthalate fiber (2.0 denier, cut length 51 mm, number of crimps: 13 / 25.4 mm) 50%
And 6-nylon fiber (2.0 denier, cut length 50m
m, number of crimps: 14 / 25.4 mm) 50%, and a laminated web was prepared by using a card and a cross layer, and a depth of 7 mm was obtained by a needle room equipped with a 40th needle having a regular barb. 700 / cm
Punching of ² was performed to obtain an entangled web. Then, pressurizing with a mirror metal roll having a surface temperature of 130 ° C.
Non-woven fabric-4 having a mm and a basis weight of 230 g / m ² was obtained.

The obtained nonwoven fabric-4 was impregnated with the impregnating liquid-1 mixed with the silicone-based additive prepared in Example 1, and thereafter the artificial comparison substrate was prepared in the same manner as in Example 1.
5 was created. The obtained artificial leather substrate-5 had a thickness of 1.0 mm, a weight of 400 g / m ² , and exhibited flexibility, elongation characteristics, abrasion resistance, and tear strength as shown in Table 1 for artificial leather. It was a well-balanced leather. As a result of observing the cross-sectional structure with an electron microscope, it was confirmed that a portion where the polyurethane was bonded to the fiber and a portion where the polyurethane was present in a non-bonded state between the fibers were mixed.

Comparative Example 3 The nonwoven fabric 1 prepared in Example 1 was replaced with a reactive silicone (H
It was treated with a 1% aqueous dispersion (silicone oil) (Geranex SH, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) and dried to prepare Non-woven Fabric-5. The obtained nonwoven fabric-5 was impregnated with the impregnating liquid-1 in which the silicone additive prepared in Example 1 was mixed. Thereafter, the same procedure as in Example 1 was carried out to prepare an artificial leather substrate-6. The obtained artificial leather substrate-6 is very soft, having a thickness of 1.0 mm and a weight of 400 g / m ² , but has other characteristics such as excessive elongation as shown in Table 1 Was unbalanced. In addition, as a result of observing the cross-sectional structure with an electron microscope, a portion where the polyurethane was bonded to the fibers was not confirmed, and it was confirmed that the polyurethane was present in a non-bonded state between the fibers.

Example 4 Polyethylene terephthalate fiber (2.0 denier, cut length 51 mm, number of crimps 13 / 25.4 mm) 60%
And polypropylene fiber (2.0 denier, cut length 50)
mm, number of crimps 13 / 25.4mm) 40%,
Create a laminated web using cards and cross layers,
Needle room equipped with 40th needle with regular barb, depth 7mm, density 700 / c
subjected to punching m ^2, and obtained the entangled web. Then
Pressing with a mirror-finished metal roll with a surface temperature of 130 ° C, the thickness is 1.
A nonwoven fabric 5 having a thickness of 0 mm and a basis weight of 230 g / m ² was obtained. On the other hand, a silicone oil (trade name: F) in which ethylene oxide was added as a silicone-based additive to the 12% polyurethane-dimethylformamide solution prepared in Example 1
G-11, manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., 46% silicone segment, 54% ethylene oxide segment, average molecular weight of about 1800) is added and mixed in an amount corresponding to 1.0 part with respect to 100 parts of polyurethane solid content, and impregnated. Liquid-3 was prepared. Next, the nonwoven fabric-5 is impregnated with the impregnating liquid-3, and thereafter, the substrate for artificial leather is processed in the same manner as in Example 1.
7 was created.

The obtained artificial leather substrate-7 had a thickness of 1.
It had a weight of 0 mm and a weight of 400 g / m ² , and the flexibility, elongation properties, abrasion resistance and tear strength were balanced as artificial leather for shoes as shown in Table 1. As a result of observing the cross-sectional structure with an electron microscope, it was confirmed that a portion where the polyurethane was bonded to the fiber and a portion where the polyurethane was present in a non-bonded state between the fibers were mixed.

Example 5 20% of polyethylene terephthalate fiber (2.0 denier, cut length 51 mm, number of crimps 13 / 25.4 mm)
And polypropylene fiber (2.0 denier, cut length 50)
mm, number of crimps 13 / 25.4mm) 80%,
Create a laminated web using cards and cross layers,
Needle room equipped with 40th needle with regular barb, depth 7mm, density 700 / c
subjected to punching m ^2, and obtained the entangled web. Then
Pressing with a mirror-finished metal roll with a surface temperature of 130 ° C, the thickness is 1.
A non-woven fabric 6 having a thickness of 0 mm and a basis weight of 230 g / m ² was obtained.

The obtained nonwoven fabric 6 is impregnated with the impregnating liquid-3 mixed with the silicone additive prepared in Example 4, and thereafter the substrate for artificial leather is produced in the same manner as in Example 1.
8 was created. The obtained artificial leather substrate-8 had a thickness of 1.0 mm, a weight of 405 g / m ² , and exhibited flexibility, elongation characteristics, abrasion resistance, and tear strength as shown in Table 1 for artificial leather. It was a well-balanced leather. As a result of observing the cross-sectional structure with an electron microscope, it was confirmed that a portion where the polyurethane was bonded to the fiber and a portion where the polyurethane was present in a non-bonded state between the fibers were mixed.

Example 6 Polyethylene terephthalate fiber (2.0 denier, cut length 51 mm, number of crimps: 13 / 25.4 mm) 50%
And 6,6-nylon fiber (1.2 denier, cut length 38
mm, number of crimp 13 / 25.4mm) 50%,
Create a laminated web using cards and cross layers,
Needle room equipped with a 40th needle with regular barb, depth 5mm, density 850 / c
subjected to punching m ^2, and obtained the entangled web. Then
Pressing with a mirror-finished metal roll with a surface temperature of 130 ° C, the thickness is 1.
A non-woven fabric 7 having a thickness of 0 mm and a basis weight of 230 g / m ² was obtained.

Next, the non-woven fabric 7 was impregnated with the impregnating solution-3 prepared in Example 4, and thereafter the artificial leather substrate 9 was prepared in the same manner as in Example 1. The obtained artificial leather substrate-9 had a thickness of 1.0 mm, a weight of 400 g / m ² , and exhibited flexibility, elongation characteristics, abrasion resistance and tear strength as shown in Table 1 for artificial leather. It was a well-balanced leather. As a result of observing the cross-sectional structure with an electron microscope, it was confirmed that a portion where the polyurethane was bonded to the fiber and a portion where the polyurethane was present in a non-bonded state between the fibers were mixed.

Example 7 Polyethylene terephthalate fiber (2.0 denier, cut length 51 mm, number of crimps: 13 / 25.4 mm) 60%
And polyethylene fiber (1.5 denier, cut length 50m
m, number of crimps: 14 / 25.4 mm) 40%, and a laminated web was prepared using a card and a cross layer. The depth was 6 mm by a needle room equipped with a 40th needle having a regular barb. 900 / cm
Punching of ² was performed to obtain an entangled web. Then, pressurizing with a mirror metal roll having a surface temperature of 130 ° C.
Non-woven fabric-8 having a mm and a basis weight of 230 g / m ² was obtained.

Next, the nonwoven fabric 8 was impregnated with the impregnating solution-1 prepared in Example 1, and thereafter, an artificial leather substrate 10 was prepared in the same manner as in Example 1. The obtained artificial leather substrate-10 had a thickness of 1.0 mm, a weight of 400 g / m ² , and exhibited flexibility, elongation characteristics, abrasion resistance, and tear strength as shown in Table 1 for artificial leather. It was a well-balanced leather. As a result of observing the cross-sectional structure with an electron microscope, it was confirmed that a portion where the polyurethane was bonded to the fiber and a portion where the polyurethane was present in a non-bonded state between the fibers were mixed.

[0049]

[Table 1]

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) D06N 3/00

Claims (10)

(57) [Claims] 1. A microporous sheet obtained by impregnating and solidifying an elastic polymer into a nonwoven fabric, wherein (1) the nonwoven fabric comprises (a) aromatic polyester fibers (fiber A) and (b) And (2) the microporous sheet-like material comprises (i) a portion where the fiber A is adhesively surrounded by an elastic polymer and the fiber. B is scattered with the portion surrounded by the elastic polymer in a non-adhered state, (ii) the softness is 0.5 to 6.0, and (ii)
i) A microporous sheet having a wear resistance of 1500 to 8000. 2. The microporous sheet according to claim 1, wherein the mixing ratio of the fiber A and the fiber B is in the range of 70:30 to 5:95 by weight. 3. The microporous sheet according to claim 1, wherein the nonwoven fabric is obtained by laminating a web made of the fibers A and a web made of the fibers B and performing an inter-fiber entanglement treatment. 4. A substrate for artificial leather comprising the microporous sheet according to claim 1 and an elastic polymer layer on at least one surface thereof. 5. The elastic polymer layer has a thickness of 20 to 500 μm.
The artificial leather substrate according to claim 4, having a thickness of: 6. A method for producing a microporous sheet by impregnating an organic polar solvent solution of an elastic polymer into a nonwoven fabric and then coagulating the solution in a coagulation bath mainly composed of water. A) a non-woven fabric in which polyester fibers (fiber A) and polyolefin fibers or nylon fibers (fiber B) are mixed, and (2) water-dispersible or water-soluble as the organic polar solution. Characterized by using a solution in which 0.1 to 10 parts by weight of a surfactant having a silicone segment as a hydrophobic group is dissolved per 100 parts by weight of the solid of the elastic polymer. Manufacturing method. 7. The method for producing a microporous sheet according to claim 6, wherein the surfactant contains 10 to 90% by weight of a silicone segment. 8. The method for producing a microporous sheet according to claim 6, wherein the surfactant is substantially formed of a polyalkylene oxide segment and a silicone segment. 9. The microporous sheet according to claim 6, wherein the surfactant contains a polyalkylene oxide segment and a silicone segment, and the ratio thereof is in the range of 10:90 to 90:10 by weight. Production method. 10. The nonwoven fabric according to claim 1, wherein the fibers A and B
The method for producing a microporous sheet-like material according to claim 6, wherein the cotton blending ratio with the mixture is in the range of 70:30 to 5:95 by weight.