JP2000303370A - Leather-like sheet and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a leather-like sheet that gives high-class sense of the suede finish with good fabric hand, touch sense and physical properties. SOLUTION: The fibrous backing material comprising fibers that can be divided into extremely fine fibrils is impregnated with a resin composite emulsion that satisfies the following conditions (i) through (iv): (i) the resin composite emulsion gels heat-sensitively. (ii) the resin composite emulsion gives a modulus of <=5.0×108 dyne/cm2, when the emulsion is dried at 50 deg.C; (iii) the resin composite emulsion gives a modulus of >=5.0×106 dyne/cm2, when the emulsion is dried at 50 deg.C; (iv) the resin composite emulsion is an emulsion that is given by emulsion polymerization of an ethylenically unsaturated monomer (A) in a polyurethane emulsion (B). Then, the impregnated fibrous backing material is coagulated and fibrillated into extremely fine fibrils.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a leather-like sheet and a method for producing the same. More specifically, the present invention relates to a leather-like sheet in which a specific composite resin emulsion is impregnated and solidified in a fibrous base material composed of ultrafine fibers, and a method for producing the same. The leather-like sheet of the present invention has significantly improved flexibility and a sense of fulfillment as compared with a conventional leather-like sheet obtained by impregnating a fibrous base material with an emulsion resin and then drying and solidifying the resin. It has a high-grade feel and touch similar to natural leather, and has excellent durability.

[0002]

2. Description of the Related Art As a substitute for natural leather (artificial leather),
2. Description of the Related Art Sheet materials in which a resin component such as polyurethane is impregnated into a fibrous base material as a binding agent have been conventionally produced. Among such sheet-like materials, when the fibrous base material is made of ultrafine fibers, it has a good feeling similar to natural leather, and is used as so-called high-grade suede-like artificial leather. As a typical production method, (1) a resin is applied to a fibrous base material composed of a sea-island type composite spun fiber or a mixed spun fiber having an ultrafine fiber, and then the sea component is treated with an organic solvent or an alkaline aqueous solution. A method of dissolving or decomposing and removing the island component as extra-fine fibers to convert the fibers constituting the fibrous base material into extra-fine fibers; and (2) a fibrous base made of extra-fine fibers already converted into extra-fine fibers. There is a method in which a material is formed in advance and a resin is applied thereto.

[0003] In the above-mentioned methods for producing artificial leather (1) and (2), as a method of applying a resin such as polyurethane to a fibrous base material, a solution in which a resin component is dissolved in an organic solvent such as dimethylformamide is used. Is wetted by impregnating the fibrous base material with water and then coagulated in a non-solvent such as water, or dried by impregnating the fibrous base material with a solution in which the resin component is dissolved in an organic solvent or an emulsion dispersed in water. Dry methods are known.

[0004] In the case of the above wet method, it is possible to obtain a sheet-like material having a feeling closer to natural leather than in the case of the dry method, but it is inferior in productivity and use of an organic solvent such as dimethylformamide. It has the disadvantage of being essential. On the other hand, among the dry methods, when using a resin emulsion, a sheet-like material can be obtained without using an organic solvent, but a high quality comparable to a leather-like sheet-like material obtained by a wet method. Has not yet been developed. The reason is that the sheet-like material obtained by the dry method has a hard feeling due to the structure in which the resin clings to the fibers and strongly restrains the fibers in the drying process, and has a higher resin texture than the sheet-like material obtained by the wet method. It is mentioned that the feeling of fulfillment is reduced due to the extremely large number of voids that do not exist.

[0005] In the above-mentioned wet method, in particular, after the resin such as polyurethane is applied to the fibrous base material, the sea component is dissolved or decomposed and removed with an organic solvent or an aqueous alkali solution to form ultrafine fibers (1). In the method of (1), the resin easily enters the ultrafine fiber bundle in the processing step and tends to strongly restrain the resin, so that the leather-like sheet material obtained often has a hard feel. In this case, if the amount of the applied resin is reduced so as not to give a hard feeling, the feeling becomes like a fibrous base material without a sense of fulfillment. Also,
In the above-described dry method using an emulsion resin, it is conceivable that the resin is applied to the fibrous base material and then treated with a softener to develop flexibility, but it is necessary to add a treatment step with a softener. Productivity is reduced, and even if a softener is added, it is difficult to give a high-grade feel similar to that of natural leather.

Further, as the above-mentioned dry method using an emulsion resin, a method of producing a base fabric for synthetic leather by impregnating a fabric with a mixed resin emulsion of a polyurethane emulsion and a polyacrylate emulsion and treating with hot water (Japanese Patent Laid-Open No. No. 55-128078) and a non-woven sheet containing a fiber layer mainly composed of ultrafine fibers having a single fiber fineness of 0.5 denier or less have an average particle size of 0.1 to 2.0.
A method has been proposed in which an emulsion is prepared by dissolving and mixing inorganic salts in a water-based polyurethane emulsion having a size of μm and then heating and drying to produce artificial leather (Japanese Patent Application Laid-Open No. Hei 6-316877). However, the artificial leather obtained by these methods is not sufficient in flexibility, fullness and the like, and it is difficult to say that the feeling is sufficiently improved. Also,
After processing a nonwoven fabric of fibers consisting of two or more polymers with an aqueous emulsion of a polyurethane resin formed from aliphatic diisocyanate, polytetramethylene glycol and aliphatic diamine, the fibers are partially decomposed with an aqueous alkaline solution or an organic solvent. Alternatively, there has been proposed a method for producing artificial leather by dissolving and ultrafine-melting (Japanese Patent Laid-Open Publication No. 9 (1998) -99).
-132876). However, the artificial leather obtained by this method has not been sufficiently improved in terms of flexibility and a sense of fulfillment.

[0007] Therefore, in the production of artificial leather,
Although high-quality artificial leather can be obtained, the wet method, in which productivity is low and the use of an organic solvent is indispensable, is currently exclusively used industrially. However, the method for producing a leather-like sheet material represented by the above-mentioned dry method of impregnating a fibrous base material with an aqueous resin emulsion and heating and coagulating the fibrous base material is performed when the fibrous base material is impregnated with the resin or impregnated with the resin. Since there is no need to use an organic solvent when coagulating the resin, it is extremely effective in terms of environmental compatibility, work environment safety, and simplification of the process. In this regard, flexibility is achieved using an aqueous resin emulsion. Also, there is a strong demand for the development of a technology capable of producing a high-quality leather-like sheet having excellent fulfillment.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a dry method using a resin emulsion, which has a fibrous base material composed of ultrafine fibers, is excellent in flexibility and fullness,
It is an object of the present invention to provide a method for producing a leather-like sheet having a suede-like high-grade feel and a leather-like sheet having a good feeling, touch and physical properties very similar to that of natural leather.

[0009]

Means for Solving the Problems As a result of repeated studies by the present inventors to achieve the above-mentioned object, a heat-sensitive gelation material having specific physical properties was added to a fibrous base material composed of ultrafine fiber-forming fibers. When impregnated with the composite resin emulsion and coagulated, and after the coagulation of the emulsion, ultrafine fiber forming fibers are ultrafine,
It has been found that a high-quality leather-like sheet material having excellent flexibility and a sense of fulfillment, having physical properties close to natural leather and comparable to the wet method can be obtained. That is, by using the specific heat-sensitive gelling emulsion and by making the fibrous base material into ultrafine fibers after application of the resin, the resin does not strongly restrain the ultrafine fibers in the fibrous base material,
It has been found that a fibrous base material is impregnated and solidified while maintaining an appropriate fiber space to obtain a high-quality leather-like sheet having excellent flexibility and a sense of fulfillment, thereby completing the present invention.

That is, according to the present invention, a fibrous base material composed of ultrafine fiber-forming fibers is impregnated with a composite resin emulsion satisfying the following conditions (i) to (iv) and solidified. (I) the composite resin emulsion is heat-sensitive gelling; (ii) drying the composite resin emulsion at 50 ° C. The elasticity modulus at 90 ° C. of the obtained film having a thickness of 100 μm is 5.0 × 10 ⁸ dyn / cm ² or less; (iii) a film having a thickness of 100 μm obtained by drying the composite resin emulsion at 50 ° C. the elastic modulus at 160 ° C. is is 5.0 × 10 ⁶ dyn / cm ² or more; and (iv) the composite resin emulsion is an ethylenically unsaturated mode in the presence of a polyurethane-based emulsion (a) Mer (B), an emulsion weight of the polyurethane in the polyurethane-based emulsion (A) weight / ethylenically unsaturated monomer (B) is obtained by emulsion polymerization in a proportion of Bu 90 / 10-10 / 90.

[0011] The present invention also relates to a leather-like sheet obtained by the above-mentioned production method.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. In the present invention, a fibrous base material composed of ultrafine fiber-forming fibers is impregnated with a composite resin emulsion and solidified, and then the ultrafine fiber-forming fibers are converted into ultrafine fibers to produce a leather-like sheet. This facilitates the process of impregnating the fibrous base material with the emulsion, and makes the obtained leather-like sheet material excellent in flexibility, fullness, natural leather-like feeling, and the like.

[0013] The fibrous base material in the present invention is not particularly limited as long as it forms a fibrous base material composed of ultrafine fibers having a moderate thickness and a sense of fulfillment and a soft feel. Various fibrous base materials forming the ultrafine fibers used in the sheet-like material can be used.

As the ultrafine fiber forming fibers constituting the fibrous base material before impregnating with the composite resin emulsion, ultrafine fiber forming composite spun fibers and / or mixed spun fibers composed of two or more kinds of polymer substances are preferable. Used. By dissolving and / or decomposing and removing a part of the polymer material constituting the composite spun fiber and / or the mixed spun fiber, and leaving the remaining polymer material in an ultrafine fibrous form, a leather-like sheet-like material is obtained. Inside, the fibrous base material can have an ultrafine fiber structure. As representative examples of the ultrafine fiber-forming composite spun fiber and / or the mixed spun fiber composed of two or more types of polymer substances, a sea-island composite spun fiber and a sea-island type mixed spun fiber composed of two or more kinds of polymer substances are exemplified. By dissolving and removing the high molecular substance forming the sea component from the fibers using an organic solvent or the like, the island component can be left in an extremely fine shape and the fibers can be formed into an ultrafine fiber. The fibrous base material used in the present invention may be formed using only one of the sea-island composite spun fiber and the sea-island mixed spun fiber, or may be formed using both.

[0015] The high molecular substance which can constitute the above-mentioned sea-island composite spun fiber or sea-island mixed spun fiber is polyethylene terephthalate, polybutylene terephthalate, or the like.
Polyesters such as modified polyester, polyamides such as 6-nylon, 6,12-nylon, 6,6-nylon, modified nylon, polyolefins such as polyethylene and polypropylene, polystyrene, polyvinylidene chloride, polyvinyl acetate, polymethacryl Acid esters, polyvinyl alcohol, polyurethane elastomers and the like can be mentioned. By selecting two or more of these polymer substances having different solubilities in organic solvents and combining them as a sea component and an island component, when the sea component is dissolved or decomposed and removed, the island component becomes an extremely fine fiber. Thus, an ultra-fine fiber-forming sea-island composite spun fiber or sea-island mixed spun fiber which can remain in the fiber can be obtained. At this time, the island component may be composed of only one kind of polymer substance or may be composed of two or more kinds of polymer substances. Two or more kinds of ultrafine fibers are present in the fibrous base material after fibrillation.

The proportion of the island component and the sea component in the ultrafine fiber-forming sea-island composite spun fiber or the sea-island mixed spun fiber is not particularly limited, but generally, the production of the composite spun fiber or the mixed spun fiber is not limited. Easiness, easiness of ultra-fine fiberization,
From the viewpoint of the physical properties of the obtained leather-like sheet, the weight ratio of island component to sea component is preferably 15:85 to 85:15, and more preferably 25:75 to 75:25. . In the case of ultrafine fiber-forming sea-island composite spun fibers or mixed sea-island spun fibers, the number and size of the island components, the state of dispersion of the island components in the sea component, and the like are not particularly limited. Any material can be used as long as the material can be obtained smoothly.

In particular, a fibrous base material formed using sea-island composite spun fiber or sea-island mixed spun fiber whose sea component is made of polyethylene and / or polystyrene and whose island component is made of polyester and / or polyamide is used. After impregnated with the composite resin emulsion and solidified, the polyethylene and / or polystyrene constituting the sea component is converted into an aromatic hydrocarbon solvent such as benzene, toluene, and xylene, and a halogenated hydrocarbon solvent such as carbon tetrachloride and perchrene. A leather-like sheet obtained by dissolving and removing an organic solvent, particularly toluene, to leave polyester and / or polyamide as an island component in the form of ultrafine fibers is excellent in flexibility and fulfillment. Suitable for artificial leather material, as it has a very good texture very close to natural leather You can use.

The fibrous base material used in the present invention may be either a nonwoven fabric and / or a knitted woven fabric, but may be composed of only a nonwoven fabric or a nonwoven fabric having a nonwoven fabric layer on at least one surface side. A laminate of a cloth and / or a knitted fabric (for example, a two-layer structure composed of a nonwoven fabric layer and a knitted fabric layer, a nonwoven fabric layer on the front and back sides and a knitted fabric layer in the center)
Layered structure) is preferably used. Examples of the nonwoven fabric preferably used as the fibrous substrate include an entangled nonwoven fabric and a wrap-type nonwoven fabric. Among them, an entangled nonwoven fabric is preferably used.

Further, the fibrous base material used in the present invention is formed by using other fiber materials together with the aforementioned ultrafine fibers, if necessary, as long as the feeling of the obtained leather-like sheet material is not impaired. May be. Examples of other fiber materials include ordinary fibers, shrinkable fibers, spontaneously extensible fibers, multi-layer laminated latent splittable fibers, special porous fibers, and the like, and one or more of these may be used in combination. it can. These other fibers are polyester fibers, polyamide fibers, acrylic fibers, polyolefin fibers,
Synthetic fibers such as polyvinyl chloride fibers, polyvinylidene chloride fibers, and polyvinyl alcohol fibers, semi-synthetic fibers, and natural fibers such as cotton, wool, and hemp can be used.

The monofilament fineness of the ultrafine fiber-forming fibers constituting the fibrous base material after ultrafine fiber formation is determined from the viewpoint that a leather-like sheet having excellent flexibility, fullness, and natural leather-like feeling can be obtained. , 0.5 denier or less, and more preferably 0.4 denier or less.

The thickness of the fibrous base material can be arbitrarily selected according to the intended use of the obtained leather-like sheet material. However, from the viewpoint of giving an appropriate leather-like feeling, the thickness of the fibrous base material before impregnation with the polyurethane emulsion is considered. The thickness is preferably from 0.3 to 3.0 mm, more preferably from 0.6 to 2.5 mm.

The apparent density of the fibrous base material is determined in the state where the fibers in the fibrous base material are in the form of ultrafine fibers (the above-mentioned sea-island type composite material) in view of the flexibility of the obtained leather-like sheet material. When the spun fiber and / or the mixed spun fiber is used, after removing the sea component to form a fine fiber), 0.1 to 0.1.
5 g / cm ³ , preferably 0.15 to 0.45
g / cm ³ is more preferable. When the apparent density of the fibrous base material is smaller than 0.1 g / cm ³ , the resulting leather-like sheet-like material tends to have poor resilience and a feeling of stiffness, and a feeling like natural leather is obtained. It becomes difficult. On the other hand, if the apparent density of the fibrous base material is larger than 0.5 g / cm ³ , the resulting leather-like sheet-like material tends to have no feeling of stiffness or have a poor rubber-like feeling.

In the present invention, in order to uniformly and rapidly impregnate the above-mentioned fibrous base material with the emulsion, the surfactant having a wet permeability to the fibrous base material prior to the emulsion impregnation is used. It is also possible to provide an aqueous solution or an aqueous emulsion. In this case, it is necessary to impregnate the composite resin emulsion without drying and removing the solvent of the aqueous solution or the dispersion medium of the dispersion from the fibrous base material to which the aqueous solution or the dispersion of the surfactant is applied. When drying is performed and the solvent of the aqueous solution or the dispersion medium of the dispersion liquid disappears, almost no effect can be expected. The amount of the surfactant provided to the fibrous base material is preferably 0.01 to 20% by weight based on the fibrous base material.

In the present invention, a fibrous base material composed of ultrafine fiber-forming fibers is impregnated with a thermogelling composite resin emulsion and solidified to produce a leather-like sheet material [the above condition (i)]. .

Here, the thermosensitive gelling emulsion referred to in the present invention means an emulsion which loses fluidity when heated and becomes a gel. The thermogelling temperature at which the thermogelling composite resin emulsion loses fluidity by heating and gels is preferably 30 to 70 ° C, more preferably 40 to 70 ° C. If the composite resin emulsion is not thermosensitive gelling, when the fibrous base material is impregnated with the emulsion and dried and gelled with hot air, the migration of the emulsion particles in the fibrous base material occurs, and the composite resin becomes a fibrous base material. Dispersion cannot be uniformly imparted to the material, and the leather-like sheet-like material has poor physical properties such as high elongation and flexibility, and has a poor feel. When the emulsion is coagulated in warm water after impregnating the fibrous base material with the composite resin emulsion, the emulsion is caused to flow out into the warm water, and the composite resin can also be uniformly dispersed and provided in the fibrous base material. As described above, the strength and elongation of the leather-like sheet,
This results in deterioration of physical properties such as flexibility and deterioration of feeling.

As the thermogelling composite resin emulsion, an emulsion containing a thermosetting gelling resin itself, or a thermosetting gelling resin obtained by adding a thermogelling agent to an emulsion is used. Any of the emulsions can be used. Examples of the thermosensitive gelling agent for obtaining a thermogelling composite resin emulsion include, for example,
Inorganic salts, polyethylene glycol-type nonionic surfactants, polyvinyl methyl ether, polypropylene glycol, silicone polyether copolymer, polysiloxane, and the like can be used, and one or more of these can be used.

Among them, a combination of an inorganic salt and a polyethylene glycol-type nonionic surfactant is preferably used as the heat-sensitive gelling agent because it exhibits good heat-sensitive gelling properties. As the inorganic salt in that case, a monovalent or divalent metal salt capable of lowering the cloud point of the polyethylene glycol type nonionic surfactant is preferably used, and specific examples thereof include sodium carbonate, sodium sulfate, and chloride. Examples thereof include calcium, calcium sulfate, zinc oxide, zinc chloride, magnesium chloride, potassium chloride, potassium carbonate, sodium nitrate, and lead nitrate. One or more of these can be used. Specific examples of the polyethylene glycol type nonionic surfactant include ethylene oxide adducts of higher alcohols, ethylene oxide adducts of alkyl phenols, ethylene oxide adducts of fatty acids, and ethylene oxide adducts of fatty acid esters of polyhydric alcohols. Examples thereof include an ethylene oxide adduct of a higher alkylamine and an ethylene oxide adduct of polypropylene glycol, and one or more of these can be used.

When a heat-sensitive gelling emulsion containing a heat-sensitive gelling agent is used, the amount of the heat-sensitive gelling agent is 0.2 to 20 parts by weight based on 100 parts by weight of the resin in the emulsion. Is preferred.

The elastic modulus at 90 ° C. of a 100 μm thick film obtained by drying the composite resin emulsion used in the present invention at a temperature of 50 ° C. is 5.0 × 10 ⁸ dyn / c.
m ² or less [condition (ii) above], 3.0 × 10 ⁸ d
yn / cm ² or less, preferably 2.0 × 10 ⁸ d
More preferably, it is yn / cm ² or less. When a composite resin emulsion that gives the dry film having an elastic modulus at 90 ° C. of more than 5.0 × 10 ⁸ dyn / cm ² is used, the resulting sheet material has a hard feeling with poor flexibility.

The elastic modulus at 160 ° C. of a 100 μm thick film obtained by drying the composite resin emulsion used in the present invention at a temperature of 50 ° C. is 5.0 × 10 ⁶ d.
yn / cm ² or more [the above condition (iii)], 8.0
× 10 ⁶ dyn / cm ² or more.
More preferably, it is at least 10 ⁷ dyn / cm ² . 1
When a composite resin emulsion having an elastic modulus at 60 ° C. of less than 5.0 × 10 ⁶ dyn / cm ² is used to give the dried film, the fibrous base material is impregnated with the emulsion and coagulated, and then solidified. When the sea component in the sea-island type composite spun fiber and / or mixed spun fiber constituting the material is extracted and removed with an organic solvent to form an ultrafine fiber, pressure is applied by a squeezing roll or the like to reduce the thickness. The result is a “bad set”, which results in a poor texture with lost flexibility, fulfillment, and waist. In the present invention, the method for measuring the elastic modulus at 90 ° C. and 160 ° C. of the dried film formed from the composite resin emulsion is as described in the following Examples.

The α-dispersion temperature (Tα) of a 100 μm thick film obtained by drying the composite resin emulsion used in the present invention at a temperature of 50 ° C. is preferably -10 ° C. or less, and -20 ° C. It is more preferable that:
When the dry film obtained from the composite resin emulsion has the above-mentioned α-dispersion temperature (Tα), the resulting leather-like sheet material has excellent physical properties such as cold resistance and bending resistance. The method for measuring the α-dispersion temperature (Tα) of the dried film in the present invention is as described in the following Examples.

The composite resin emulsion used in the present invention is
In the presence of the polyurethane-based emulsion (A), the ethylenically unsaturated monomer (B) was mixed with the polyurethane-based emulsion (A) at a ratio of 90/10 to 10 / (weight of polyurethane / weight of ethylenically unsaturated monomer (B)). An emulsion obtained by emulsion polymerization at a ratio of 90 [condition (iv) above].

The polyurethane contained in the polyurethane emulsion (A) is generally a polymer polyol,
It can be produced by appropriately combining and reacting an organic diisocyanate compound and a chain extender.

The above-mentioned high molecular polyol used in the production of polyurethane includes polyester polyol,
Polyether polyols, polycarbonate polyols, polyester polycarbonate polyols and the like can be mentioned, and polyurethane can be formed using one or more of these polymer polyols.

Polyester polyols that can be used in the production of polyurethane are prepared by directly esterifying a polyol component with a polycarboxylic acid component such as a polycarboxylic acid, an ester thereof, or an ester-forming derivative such as an anhydride, according to a conventional method. Alternatively, it can be produced by a transesterification reaction. Further, the polyester polyol can also be produced by ring-opening polymerization of lactone.

As a polycarboxylic acid component which is a raw material for producing a polyester polyol which can be used for producing a polyurethane, those generally used in the production of polyester can be used. For example, succinic acid, glutaric acid, adipine Acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, methyl succinic acid,
Aliphatic having 4 to 12 carbon atoms such as 2-methylglutaric acid, 3-methylglutaric acid, trimethyladipic acid, 2-methyloctanedioic acid, 3,8-dimethyldecandioic acid, and 3,7-dimethyldecandioic acid Dicarboxylic acids; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, and naphthalenedicarboxylic acid; tricarboxylic acids such as trimellitic acid and trimesic acid; And the like, and the polyester polyol can be formed using one or more of the above-mentioned polycarboxylic acid components. Among them, the polyester polyol is preferably produced using an aliphatic dicarboxylic acid or an ester-forming derivative thereof as a polycarboxylic acid component.

As the polyol component which is a raw material for producing a polyester polyol which can be used for producing polyurethane, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol,
1,3-propanediol, 2-methyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1,3-butylene glycol, 1,4-butanediol, 3-methyl-1 , 5-pentanediol,
1,6-hexanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, 2,7-
Aliphatic diols having 2 to 15 carbon atoms such as dimethyl-1,8-octanediol, 1,9-nonanediol, 2,8-dimethyl-1,9-nonanediol, and 1,10-decanediol; Alicyclic diols such as cyclohexanediol, cyclohexanedimethanol and dimethylcyclooctanedimethanol; 1,4-bis (β-
Aromatic diols such as hydroxyethoxy) benzene;
Polyalkylene glycols; polyols such as glycerin, trimethylolpropane, butanetriol, and pentaerythritol can be mentioned, and one or more of the above-mentioned polyol components can be used. Among them, the polyester polyol is preferably produced using an aliphatic polyol.

As a lactone which is a raw material for producing a polyester polyol which can be used for producing a polyurethane, for example, ε-caprolactone, β-methyl-δ-valerolactone and the like can be mentioned.

Examples of the polyether polyols that can be used in the production of polyurethane include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, poly (methyltetramethylene glycol), and one or more of these. Can be used.

Examples of the polycarbonate polyol that can be used for producing polyurethane include polycarbonate polyol obtained by reacting the polyol with a carbonate compound such as dialkyl carbonate, diaryl carbonate, or alkylene carbonate. As the polyol which is a raw material for producing a polycarbonate polyol, those exemplified as the polyol which is a raw material for producing a polyester polyol can be used. Dialkyl carbonate includes dimethyl carbonate, diethyl carbonate, and the like, diaryl carbonate includes diphenyl carbonate, and the like, and alkylene carbonate includes ethylene carbonate.

Examples of the polyester polycarbonate polyols that can be used in the production of polyurethane include those obtained by simultaneously reacting a polyol, a polycarboxylic acid and a carbonate compound, and those obtained by reacting a polyester polyol and a polycarbonate polyol prepared in advance with a carbonate compound. And the like.

The number average molecular weight of the high molecular polyol used for producing the polyurethane is preferably from 500 to 10,000, more preferably from 700 to 5,000, and
More preferably, it is 50 to 4000. The number average molecular weight of the high molecular polyol referred to in the present specification is JIS.
It refers to the number average molecular weight calculated based on the hydroxyl value measured according to K1577.

The number of hydroxyl groups per molecule of the high molecular polyol used in the production of polyurethane may be larger than 2 as long as the production of the polyurethane emulsion (A) is not hindered. The polymer polyol having more than 2 hydroxyl groups per molecule is, for example, in the case of a polyester polyol, glycerin, trimethylolpropane, butanetriol, hexanetriol, trimethylolbutane, pentaerythritol, etc. Can be produced by using the polyol as a part of the polyol component.

The type of the organic diisocyanate compound used in the production of the polyurethane is not particularly limited, and known aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates having an isocyanate group in the molecule conventionally used in the production of polyurethane emulsions are used. Any of the group diisocyanates can be used. Specific examples of the organic diisocyanate compound that can be used for the production of polyurethane include isophorone diisocyanate, tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, p
-Phenylene diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 3,3'-dichloro-4,
Examples thereof include 4′-diphenylmethane diisocyanate and hydrogenated xylylene diisocyanate, and one or more of these organic diisocyanates can be used.

Among the organic isocyanate compounds described above, aromatic diisocyanates such as tolylene diisocyanate and 4,4'-diphenylmethane diisocyanate are preferably used because the resulting polyurethane has excellent solvent resistance. In the case of using a polyurethane-based emulsion containing polyurethane obtained by using an aromatic diisocyanate, a fibrous base material composed of sea-island composite spun fibers and / or mixed spun fibers is impregnated with the polyurethane-based emulsion and coagulated. When the sea component is extracted and removed with an organic solvent to form ultrafine fibers, the polyurethane has excellent solvent resistance, so the deterioration in physical properties of the polyurethane due to the organic solvent is suppressed, and the leather has excellent feeling and mechanical properties. A sheet-like material can be obtained.

As the chain extender used in the production of the polyurethane, any of the chain extenders conventionally used in the production of polyurethane-based emulsions can be used. Among them, an active hydrogen atom capable of reacting with an isocyanate group is used in the molecule. A low molecular weight compound having a molecular weight of 400 or less having two or more is preferably used. Such chain extenders include, for example, hydrazine, ethylenediamine, propylenediamine, isophoronediamine, piperazine and derivatives thereof, phenylenediamine, tolylenediamine, xylylenediamine, adipic dihydrazide, isophthalic dihydrazide, hexamethylene diamine, 4 Diamines such as 4,4'-diaminophenylmethane and 4,4'-dicyclohexylmethanediamine; triamines such as diethylenetriamine; ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 3-methyl -1,5-pentanediol, neopentyl glycol, 1,4-cyclohexanediol, bis- (β-hydroxyethyl) terephthalate,
Diols such as xylylene glycol and 1,4-bis (β-hydroxyethoxy) benzene; amino alcohols such as aminoethyl alcohol and aminopropyl alcohol; and the like, and one or more of these may be used. be able to. Among these, ethylene glycol, isophoronediamine, ethylenediamine, diethylenetriamine and the like are preferably used.

The polyurethane emulsion (A) has a polyurethane skeleton based on 100 g of polyurethane in the polyurethane skeleton in view of the polymerization stability at the time of emulsion polymerization of the ethylenically unsaturated monomer (B) and the ease of imparting heat-sensitive gelling properties. 3-30m
It preferably has mol neutralized carboxyl or sulfonic acid groups. Introduction of a neutralized carboxyl group or sulfonic acid group into the polyurethane skeleton,
As a raw material for producing polyurethane, a compound having a carboxyl group, a sulfonic acid group, or a salt thereof and containing at least one active hydrogen atom such as a hydroxyl group or an amino group is used in combination. This is achieved by neutralization with a basic substance such as a metal hydroxide. Examples of such compounds include carboxylic acid group-containing compounds such as 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (hydroxymethyl) butyric acid, and 2,2-bis (hydroxymethyl) valeric acid And derivatives thereof; sulfonic acid group-containing compounds such as 1,3-phenylenediamine-4,6-disulfonic acid and 2,4-diaminotoluene-5-sulfonic acid, and derivatives thereof. Further, polyester polyols or polyester polycarbonate polyols obtained by copolymerizing the above compounds can also be used. Among them,
A method in which a polyurethane prepolymer is produced using 2,2-bis (hydroxymethyl) propionic acid, and neutralized by adding a basic substance such as triethylamine, trimethylamine, sodium hydroxide, or potassium hydroxide after completion of the prepolymer reaction. Is preferred.

In the production of polyurethane, a trifunctional or higher functional polyol such as trimethylolpropane or a trifunctional or higher amine is reacted as required for the purpose of improving solvent resistance, heat resistance, hot water resistance and the like. The polyurethane may have a crosslinked structure.

The polyurethane emulsion (A) used in the present invention can be produced by a method similar to that conventionally used for producing a polyurethane emulsion. For example, (1) having an isocyanate group at the terminal Polyurethane prepared by producing a urethane prepolymer and forcibly emulsifying the prepolymer in water with high mechanical shearing force in the presence of an emulsifier, or simultaneously completing the chain extension reaction with a suitable chain extender to increase the molecular weight A method for producing an emulsion, (2) a method for producing a self-emulsifying polyurethane using a hydrophilic polymer polyol, and emulsifying the same in water without using an emulsifier to produce a polyurethane emulsion. Can be mentioned. For the emulsification, an emulsifying and dispersing device such as a homomixer and a homogenizer can be used. In this case, the emulsifying temperature is preferably set to 40 ° C. or lower in order to suppress the reaction between the isocyanate group and water.

The polyurethane emulsion (A) has the above-mentioned (1) in view of the polymerization stability when the ethylenically unsaturated monomer (B) is emulsion-polymerized in the presence thereof and the ease of imparting the thermosensitive gelling property. The emulsifier in the above method preferably contains 0.5 to 10 g of a surfactant based on 100 g of the polyurethane. Examples of such surfactants include anionic surfactants such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium polyoxyethylene tridecyl ether acetate, sodium dodecyl benzene sulfonate, sodium alkyl diphenyl ether disulfonate, and sodium di (2-ethylhexyl) sulfosuccinate. Surfactants: Nonionic surfactants such as polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene-polyoxypropylene block copolymer, etc. Among these, sodium lauryl sulfate, sodium polyoxyethylene tridecyl ether acetate, ammonium lauryl sulfate, etc. Emissions surfactants are preferred.

The composite resin emulsion used in the present invention is produced by emulsion polymerization of an ethylenically unsaturated monomer (B) in the presence of a polyurethane emulsion (A).
The weight ratio of the polyurethane and the ethylenically unsaturated monomer (B) in the polyurethane emulsion (A) is 90 /
10/90/90, preferably 85/15/15/85, and more preferably 80 / 20-20 / 80. When the proportion of the polyurethane is less than 10% by weight, the modulus of elasticity of the composite resin is increased, and the feeling of the obtained leather-like sheet is inferior. On the other hand, when the proportion of the polyurethane exceeds 90% by weight, the weather resistance and hydrolysis resistance of the composite resin are inferior and the cost is high.

As the ethylenically unsaturated monomer (B), 90 to 99.9% by weight of a monofunctional ethylenically unsaturated monomer (B1) mainly composed of a (meth) acrylic acid derivative and a bifunctional or higher polyfunctional ethylenically unsaturated monomer (B1) are used. The content of the saturated monomer (B2) is preferably from 10 to 0.1% by weight because the leather-like sheet obtained is more excellent in feeling and weather resistance, and the monofunctional ethylenically unsaturated monomer (B1) 9
More preferably, it comprises 2 to 99.8% by weight and 8 to 0.2% by weight of the polyfunctional ethylenically unsaturated monomer (B2).

The monofunctional ethylenically unsaturated monomer (B1) used for producing the composite resin emulsion includes:
Methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, (meth) acrylic acid 2
-Ethylhexyl, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, (meth)
Benzyl acrylate, (meth) acrylic acid, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate,
(Meth) acrylic acid derivatives such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; aromatic vinyl compounds such as styrene, α-methylstyrene and p-methylstyrene; acrylamide, diacetone Acrylamides such as acrylamide, methacrylamide, and maleic amide; maleic acid, fumaric acid, itaconic acid and derivatives thereof; heterocyclic vinyl compounds such as vinylpyrrolidone; vinyl compounds such as vinyl chloride, acrylonitrile, vinyl ether, vinyl ketone, and vinylamide Α-olefins such as ethylene and propylene, and one or more of these can be used. Among them, as the monofunctional ethylenically unsaturated monomer (B1), the proportion of the (meth) acrylic acid derivative is preferably at least 60% by weight, more preferably at least 70% by weight, and at least 80% by weight. Is more preferred.

Bifunctional or higher functional polyfunctional ethylenically unsaturated monomer (B2) used for producing a composite resin emulsion
Examples thereof include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, and 1,6. Di-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, dimethylol tricyclodecane di (meth) acrylate, glycerin di (meth) acrylate, etc. (Meth) acrylates; Tri (meth) acrylates such as trimethylolpropane tri (meth) acrylate and pentaerythritol tri (meth) acrylate; Tetra such as pentaerythritol tetra (meth) acrylate (Meth) acrylates; polyfunctional aromatic vinyl compounds such as divinylbenzene and trivinylbenzene; two or more different ethylenically unsaturated bond-containing compounds such as allyl (meth) acrylate and vinyl (meth) acrylate; 2-hydroxy -3-phenoxypropyl acrylate and hexamethylene diisocyanate 2: 1 addition reaction product, pentaerythritol triacrylate and hexamethylene diisocyanate 2: 1 addition reaction product, glycerin dimethacrylate and tolylene diisocyanate 2: 1 addition reaction product, etc. Examples thereof include urethane acrylates having a molecular weight of 1500 or less, and one or more of these can be used.

The addition of the ethylenically unsaturated monomer (B) to the polyurethane emulsion (A) can be carried out at once,
Any of continuous and continuous methods may be used, and multi-stage polymerization in which the monomer composition is changed at each polymerization stage or polymerization by a power feed method in which the monomer composition is continuously changed may be performed. In the case of multi-stage polymerization or polymerization by the power feed method, the total amount of the bifunctional or higher polyfunctional ethylenically unsaturated monomer (B2) among the total ethylenically unsaturated monomers (B) used for polymerization is 0.1 to 0.1%. Preferably, it is 10% by weight. Further, an emulsifier such as a surfactant may be appropriately added during the polymerization of the ethylenically unsaturated monomer (B).

Examples of the polymerization initiator used for the polymerization of the ethylenically unsaturated monomer (B) include benzoyl peroxide, lauroyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, cumene hydroperoxide, t Oil-soluble peroxides such as -butyl hydroperoxide, diisopropylbenzene hydroperoxide;
Oil-soluble azo compounds such as 2,2'-azobisisobutyronitrile and 2,2'-azobis- (2,4-dimethylvaleronitrile); hydrogen peroxide, potassium persulfate, sodium persulfate, ammonium persulfate, etc. Water-soluble peroxides; water-soluble azo compounds such as azobiscyanovaleric acid and 2,2'-azobis- (2-amidinopropane) dihydrochloride; and one or more of these are used. Can be. Among these, it is preferable to use an oil-soluble initiator such as an oil-soluble peroxide and an oil-soluble azo compound. Further, a redox initiator system using a reducing agent and, if necessary, a chelating agent together with the polymerization initiator may be used. Examples of the reducing agent include formaldehyde alkali metal sulfoxylates such as Rongalit (formaldehyde sodium sulfoxylate); sulfites such as sodium sulfite and sodium hydrogen sulfite; pyrosulfites such as sodium pyrosulfite; sodium thiosulfate and the like Thiosulfates; phosphites such as phosphorous acid and sodium phosphite; pyrophosphites such as sodium pyrophosphite; mercaptans; ascorbic acids such as ascorbic acid and sodium ascorbate; erythorbic acid;
Erythorbic acid salts such as sodium erythorbate; sugars such as glucose and dextrose; and metal salts such as ferrous sulfate and copper sulfate. As a chelating agent,
Examples include sodium pyrophosphate and ethylenediaminetetraacetate. The amounts of these initiators, reducing agents and chelating agents used are determined according to the combination of the respective initiator systems.

The composite resin emulsion used in the present invention may contain another polymer in the emulsion as long as the properties of the obtained leather-like sheet are not impaired.
As such other polymers, for example, acrylonitrile-butadiene copolymer, polybutadiene, synthetic rubber such as polyisoprene, ethylene-propylene copolymer, polyacrylate, acrylic copolymer, silicone, other polyurethane, Examples include elastic synthetic polymers such as polyvinyl acetate, polyvinyl chloride, polyester-polyether block copolymer, and ethylene-vinyl acetate copolymer. The composite resin emulsion can contain one or more of these polymers.

The composite resin emulsion may be used, if necessary,
Further known additives, for example, surfactants such as antioxidants, ultraviolet absorbers, penetrants, thickeners, fungicides, water-soluble polymer compounds such as polyvinyl alcohol and carboxymethyl cellulose, dyes, pigments, filling One or two or more agents, coagulation regulators and the like may be contained.

The method of impregnating the fibrous base material composed of the ultrafine fiber-forming fibers with the composite resin emulsion may be any method as long as it can uniformly impregnate the fibrous base material with the emulsion. Specifically, a method of dipping a fibrous base material in a composite resin emulsion is preferably employed. Furthermore, after impregnating the fibrous base material with the emulsion,
The impregnation amount of the emulsion can be adjusted to an appropriate amount using a press roll, a doctor knife, or the like.

Next, the composite resin emulsion impregnated in the fibrous base material is solidified by heating. Examples of the method of heat coagulation of the composite resin emulsion include (1) a method in which a fibrous base material impregnated with the emulsion is coagulated by dipping in a hot water bath at 70 to 100 ° C., and (2) a fiber material impregnated with the emulsion. A method of coagulating by spraying heated steam at 100 to 200 ° C. on the base material, and (3) a method of coagulating the fibrous base material impregnated with the emulsion by directly introducing it into a drying device at 50 to 150 ° C. and drying by dry heat. And the like. Among them, the coagulation method in a warm water bath of the above (1) or the coagulation method using heated steam of the above (2) is preferably adopted from the viewpoint of obtaining a leather-like sheet having a more flexible feel. . In the above methods (1) to (3), the temperature at which the composite resin emulsion is coagulated is set so that the coagulation of the emulsion is promptly completed to prevent uneven distribution of the composite resin in the fibrous base material. The temperature is preferably 10 ° C. or more higher than the thermal gelation temperature. Further, in the case where the coagulation method (1) or (2) is used, subsequently, heat drying or air drying is performed to remove moisture contained in the leather-like sheet.

In the leather-like sheet finally obtained by impregnating the fibrous base material with the composite resin emulsion, coagulating and drying, the amount of the polymer adhered to the leather-like sheet (the composite resin emulsion is When the polymer of the present invention is contained, the total amount of the polymer including the composite resin is preferably 5 to 150% by weight based on the weight of the fibrous base material after ultrafine fiber formation, and 10 to 100% by weight. %, More preferably from 20 to 80% by weight. If the attached amount of the polymer is less than 5% by weight, the obtained leather-like sheet-like material tends to lack a sense of fulfillment and tend to not have a natural leather-like feeling. There is a tendency that the leather-like sheet material to be obtained becomes hard and the texture like natural leather cannot be obtained.

In the present invention, a leather-like sheet is produced by impregnating the composite resin emulsion and coagulating it, and then subjecting the ultrafine fiber forming fibers constituting the fibrous base material to ultrafine fibers. At that time, when the fibrous base material is formed from the above-mentioned sea-island type composite spun fiber and / or sea-island type mixed spun fiber, impregnation of the composite resin emulsion,
After coagulation, the sea component in the fiber is dissolved and removed using an organic solvent to leave the island component in the form of ultrafine fibers, thereby producing the leather-like sheet of the present invention. In this case, the removal of the sea component with the organic solvent can be performed according to known methods and conditions conventionally used in the production of artificial leather and the like. The step of performing ultrafine fiber formation of the ultrafine fiber forming fiber after coagulation of the composite resin emulsion is to remove the sea component of the sea-island type fiber bound by the composite resin, and to make the ultrafine fiber which is an island component not in contact with the composite resin. As a result, the resultant leather-like sheet has an effect of weakening the constraint of the composite resin on the fibrous base material composed of ultrafine fibers as a whole.

The leather-like sheet material of the present invention obtained as described above is rich in flexibility, at the same time has a sense of fulfillment, has a very good feeling similar to that of natural leather, and is obtained by the conventional wet coagulation method. There is no inferiority compared with the artificial leather obtained by the method. As a result of the observation by the electron microscope of the present inventors, in the leather-like sheet-like material according to the present invention, the composite resin does not strongly restrain the fine fibers in the fibrous base material, while leaving a suitable space between the fine fibers. It was observed that the voids were filled and solidified. Therefore, in the leather-like sheet of the present invention,
The restraint of the fiber, the reduction in flexibility caused by the sagging of the sheet-like material is prevented, and the filling amount of the apparent resin portion is increased by filling the gap between the fibers while leaving a space between the fibers, Compared to the conventional emulsion-impregnated leather-like sheet, a leather-like sheet having a feeling of fulfillment and excellent feeling very similar to natural leather can be obtained while maintaining good flexibility. .

The leather-like sheet material of the present invention takes advantage of the above-mentioned excellent properties to make use of, for example, mattresses, bag lining materials, clothing interlining, shoe interlining, cushioning materials, automobiles, trains, aircraft and the like. It can be effectively used for a wide range of applications such as interior materials, wall materials, carpets and the like. Further, by buffing, a suede-like leather-like sheet is obtained, which can be suitably used as a lining material for clothes, furniture such as chairs and sofas, a lining material for train and automobile seats, wallpaper, gloves, and the like. Can be. Also, by providing a polyurethane layer or the like on one side of the leather-like sheet of the present invention by a known method, sports shoes, men's shoes,
It can also be suitably used as artificial leather with silver used for bags, handbags, school bags, and the like.

[0065]

EXAMPLES The present invention will be described below in more detail with reference to examples and the like, but the present invention is not limited to these examples. In the following Examples and Comparative Examples, the heat-sensitive gelation temperature of the emulsion and the 9
The elastic modulus at 0 ° C. and 160 ° C., α-dispersion, flexibility of the sheet, and feeling were evaluated by the following methods.

[Thermal Gelation Temperature] 10 g of the emulsion was weighed into a test tube, and the temperature was raised while stirring in a constant temperature hot water bath at 90 ° C. to obtain an emulsion when the emulsion lost its fluidity and became a gel. This temperature was defined as the thermosensitive gelling temperature.

[Elastic modulus at 90 ° C. and 160 ° C., α-dispersion] The emulsion obtained by drying the emulsion at 50 ° C.
After heat-treating the 0 μm film at 130 ° C. for 10 minutes, the film was measured at a frequency of 11 Hz using a viscoelasticity measuring device (FT rheospector “DVE-V4” manufactured by Rheology), and the elastic modulus at 90 ° C. and 160 ° C. (E ′) and the temperature of α dispersion (Tα) were determined.

[Flexibility] 10 × 10
cm, and a pure bending tester (“KES-FB2-L” manufactured by KATO TEKKO) with the room temperature at 20 ° C.
The bending rigidity (gfcm ^{2) in the} direction perpendicular to the winding direction of the nonwoven fabric used for producing the leather-like sheet material
/ Cm) as an index of flexibility.

[Bending resistance] A leather-like sheet was 7 × 4.
Cut to 5 cm, flex resistance tester (Bally “Flexometer”) according to JIS-K6545
And a bending test was performed at a temperature of 20 ° C. The surface condition of the sheet was observed every 100,000 times of bending, and the number of times until cracks or holes were formed was measured. When cracking or puncturing did not occur even after 500,000 times, bending resistance was sufficiently good and durability was evaluated as "O".

[Hand] Touch a leather-like sheet with a hand,
A case having a natural leather-like texture is judged to be “」 ”, and is harder than natural leather and lacks flexibility, and / or
Or, the case where the feeling of fulfillment was insufficient and did not have the texture of natural leather was judged as "x".

The abbreviations of the compounds used in the text are shown in Tables 1 and 2.

[0072]

[Table 1]

[0073]

[Table 2]

[Reference Example 1] << Production of fibrous base material >> 60 parts by weight of 6-nylon and polyethylene 40 having high fluidity
A part by weight is mixed and spun, stretched and cut to obtain a sea-island type mixed spun fiber (single fiber fineness 4 denier, fiber length 5
1 mm, 6-nylon is an island component), through each process of card, cross wrapper, and needle punch,
An entangled nonwoven fabric having an apparent density of 0.160 g / cm ³ was produced. This non-woven fabric was heated to melt polyethylene as a sea component and heat-set between the fibers to obtain an apparent density of 0.285.
An entangled nonwoven fabric (hereinafter, referred to as nonwoven fabric) having both surfaces smoothed in g / cm ³ was obtained.

Reference Example 2 << Manufacture of fibrous base material >> Sea-island composite spun fiber (single fiber fineness: 4 denier, fiber length: 51 mm, polyethylene: 70 parts by weight of polyethylene terephthalate and 30 parts by weight of low density polyethylene) Terephthalate is an island component, and the number of islands in the fiber cross section is 15
Using this method, an entangled nonwoven fabric is manufactured through the steps of card, cross wrapper, and needle punch, and then immersed in hot water at 70 ° C. to reduce the area shrinkage by 30%.
After shrinking so as to become, polyethylene as a sea component is melted and heat-fixed between the fibers to give an apparent density of 0.35 g.
/ Cm ³ , an entangled nonwoven fabric (hereinafter referred to as nonwoven fabric) having both surfaces smoothed was obtained.

Reference Example 3 << Manufacture of Fibrous Substrate >> Sea-island composite spun fiber (single fiber fineness: 4 denier, fiber length: 51 mm, polyethylene terephthalate) manufactured using 70 parts by weight of polyethylene terephthalate and 30 parts by weight of polystyrene In the same manner as in Reference Example 2, the fibers were heat-fixed using the island component and the number of islands in the fiber cross section of 15).
An entangled nonwoven fabric (hereinafter referred to as nonwoven fabric) having an apparent density of 0.32 g / cm ³ and having both surfaces smoothed was obtained.

Reference Example 4 << Production of Polyurethane Emulsion >> A three-necked flask was charged with 300.0 g of PMPA2000,
60.87 g of TDI and 7.85 g of DMPA were weighed and stirred at 90 ° C. for 2 hours in a dry nitrogen atmosphere to quantitatively react hydroxyl groups in the system to obtain an isocyanate-terminated prepolymer. After adding 195.4 g of MEK thereto and uniformly stirring, the temperature in the flask was lowered to 40 ° C.
5.92 g of EA was added and stirred for 10 minutes. Next, 7.83 g of sodium lauryl sulfate was used as an emulsifier.
Was dissolved in 285.0 g of distilled water, added to the prepolymer, stirred for 1 minute with a homomixer and emulsified, and immediately thereafter, 6.91 g of DETA and 5.70 of IPDA were obtained.
g was dissolved in 496.4 g of distilled water, and the mixture was stirred for 1 minute with a homomixer to carry out a chain extension reaction. Thereafter, MEK was removed by a rotary evaporator to obtain a polyurethane emulsion having a solid content of 35% by weight (hereinafter, referred to as PU).

Reference Example 5 << Production of Polyurethane Emulsion >> In a three-necked flask, 200.0 g of PHC2000, P
TMG1000 100.0 g, MDI 105.1
g and 8.85 g of DMPA were weighed and stirred at 90 ° C. for 2 hours under a dry nitrogen atmosphere to quantitatively react hydroxyl groups in the system to obtain an isocyanate-terminated prepolymer. After adding 219.1 g of MEK to this and stirring uniformly,
The temperature in the flask was lowered to 40 ° C., and 6.68 g of TEA was added, followed by stirring for 10 minutes. Next, sodium polyoxyethylene tridecyl ether acetate (anionic emulsifier; Nippon Surfactant “ECT”) was used as an emulsifier.
-3NEX ”), an aqueous solution obtained by dissolving 13.17 g in 319.9 g of distilled water was added to the prepolymer, and the mixture was emulsified by stirring with a homomixer for 1 minute.
2g, IPDA 11.20g and distilled water 538.0g
Was added thereto, and the mixture was stirred with a homomixer for 1 minute to perform a chain extension reaction. Thereafter, MEK was removed by a rotary evaporator to obtain a polyurethane emulsion having a solid content of 35% by weight (hereinafter, referred to as PU).

Reference Example 6 << Production of Polyurethane Emulsion >> In a three-necked flask, 300.0 g of PCL2000, T
70.53 g of DI and 10.06 g of DMPA were weighed and stirred at 90 ° C. for 2 hours in a dry nitrogen atmosphere to quantitatively react hydroxyl groups in the system to obtain an isocyanate-terminated prepolymer. After adding 204.4 g of MEK to the mixture and uniformly stirring, the temperature in the flask was lowered to 40 ° C.
EA (7.59 g) was added and the mixture was stirred for 10 minutes. Then sodium lauryl sulfate 12.29 as emulsifier
g of distilled water dissolved in 296.3 g of distilled water was added to the prepolymer, and the mixture was emulsified by stirring with a homomixer for 1 minute, and immediately thereafter, 8.82 g of DETA and 2.57 g of EDA were obtained.
Was dissolved in 521.2 g of distilled water, and the mixture was stirred for 1 minute with a homomixer to carry out a chain extension reaction. Thereafter, MEK was removed by a rotary evaporator to obtain a polyurethane emulsion having a solid content of 35% by weight (hereinafter, referred to as PU).

<< Production of Composite Resin Emulsion and Leather-Like Sheet Material >> [Example 1] 240 g of PU obtained in Reference Example 3 and ferrous sulfate heptahydrate (FeSO ₄
・ 7H ₂ O) 0.020 g, potassium pyrophosphate
0.294 g, Rongalit (formaldehyde sodium sulfoxylate dihydrate) 0.451 g, EDT
After 0.020 g of A.2Na and 246 g of distilled water were weighed and heated to 40 ° C., the inside of the system was sufficiently purged with nitrogen.
Then, BA 152.1 g, HDDA 3.14 g,
1.57 g of ALMA and ECT-3NEX1.57
g of the mixture (monomer), 0.314 g of CHP,
0.314 g of ECT-3NEX and 15.0 of distilled water
g of the emulsion (initiator) was dropped into the flask from a separate dropping funnel over 4 hours.
For 30 minutes. Then, 38.4 g of MMA, H
0.78 g DDA and ECT-3NEX 0.39
2 g of the mixture (monomer) and CHP 0.078
g, ECT-3NEX 0.078 g and distilled water
3.0 g of the emulsion (initiator) was dropped into the flask over a period of 1 hour and 30 minutes from a separate dropping funnel, and after completion of the dropping, the mixture was maintained at 50 ° C. for 60 minutes to complete the polymerization. A 40% by weight emulsion was obtained. To 100 parts by weight of this emulsion, 4 parts by weight of a nonionic surfactant ("Emulgen 109P" manufactured by Kao) and 1 part by weight of calcium chloride were blended to obtain an emulsion having a thermosensitive gelling property. The thermal gelation temperature of this emulsion, 90 ° C of the film obtained by drying the emulsion and 16 ° C
The elastic modulus and the α-dispersion temperature (Tα) at 0 were as shown in Table 4.

The nonwoven fabric obtained in Reference Example 1 was immersed in the bath of the above thermosensitive gelling emulsion to impregnate the thermogelling emulsion, taken out of the bath, squeezed with a press roll, and then heated to 90 ° C. In a hot water bath for 1 minute to solidify the thermosensitive gelling emulsion,
It dried in the hot-air dryer of 30 degreeC for 30 minutes, and manufactured the sheet-like material. Next, the sheet was immersed in toluene at a temperature of 90 ° C., and immersed in a press roll of ² kg / cm ² during immersion.
The squeezing process is repeated to dissolve and remove the sea component (polyethylene) in the sea-island type mixed spun fiber constituting the nonwoven fabric, and the composite resin is impregnated and solidified in the 6-nylon ultrafine fiber bundle entangled nonwoven fabric. Leather-like sheets were produced.
The attached weight of the composite resin in the leather-like sheet was 57% by weight based on the weight of the nonwoven fabric after the ultrafine fiber treatment. As shown in Table 4, this sheet was a natural leather-like sheet having flexibility and a sense of fulfillment, and excellent feeling and durability.

Example 2 In the same manner as in Example 1, an emulsion having a thermosensitive gelling property was obtained using the raw materials shown in Table 3. The thermal gelation temperature of this emulsion, 90 ° C of the film obtained by drying the emulsion and 16 ° C
The elastic modulus and α dispersion temperature at 0 ° C. were as shown in Table 4. The non-woven fabric obtained in Reference Example 2 is impregnated with and imparted with the above thermosensitive gelling emulsion in the same manner as in Example 1 to produce a sheet, and then immersed in toluene at a temperature of 90 ° C. The sea component (polyethylene) in the sea-island type composite spun fiber constituting the nonwoven fabric is subjected to a squeezing process 5 times with a press roll of ² kg / cm ² therein.
Was dissolved and removed to obtain a leather-like sheet in which the composite resin was impregnated and solidified in the ultrafine fiber entangled nonwoven fabric of polyethylene terephthalate. The adhesion weight of the composite resin of the leather-like sheet is 5% of the weight of the nonwoven fabric after the ultrafine fiberizing treatment.
It was 2% by weight. As shown in Table 4, this sheet was a natural leather-like sheet having flexibility and a sense of fulfillment, and excellent feeling and durability.

Example 3 In the same manner as in Example 1, an emulsion having a thermosensitive gelling property was obtained using the raw materials shown in Table 3. The thermal gelation temperature of this emulsion, 90 ° C of the film obtained by drying the emulsion and 16 ° C
The elastic modulus and α dispersion temperature at 0 ° C. were as shown in Table 4. The nonwoven fabric obtained in Reference Example 3 was immersed in the bath of the thermogelling emulsion to impregnate the thermogelling emulsion, taken out of the bath, squeezed with a press roll, and then 1.5 kg / cm. Steam having a pressure of ² was sprayed on the whole to solidify the thermosensitive gelling emulsion, and further dried in a hot air dryer at 130 ° C. for 30 minutes to produce a sheet-like material. Next, this sheet is immersed in toluene at a temperature of 90 ° C.
The squeezing process is performed five times with a press roll of m ² to dissolve and remove the sea component (polystyrene) in the sea-island type composite spun fiber constituting the nonwoven fabric, and the composite is formed into a polyethylene terephthalate ultrafine fiber bundle entangled nonwoven fabric. A leather-like sheet in which the resin was impregnated and solidified was obtained. The attached weight of the composite resin on the leather-like sheet was 61% by weight based on the weight of the nonwoven fabric after the ultrafine fiber treatment. As shown in Table 4, this sheet was a natural leather-like sheet having flexibility and a sense of fulfillment, and excellent feeling and durability.

Example 4 In the same manner as in Example 1, an emulsion having a thermosensitive gelling property was obtained using the raw materials shown in Table 3. The thermal gelation temperature of this emulsion, 90 ° C of the film obtained by drying the emulsion and 16 ° C
The elastic modulus and α dispersion temperature at 0 ° C. were as shown in Table 4. The above thermosensitive gelling emulsion 100
After adding 0.5 part by weight of a substrate wetting agent (“Polyflow KL-260” manufactured by TCS) as a penetrant to the part by weight, the nonwoven fabric obtained in Reference Example 1 is immersed in a bath of this emulsion. Impregnated with the thermosensitive gelling emulsion, taken out of the bath, squeezed with a press roll,
The sheet was heated in a hot air drier at 0 ° C. for 30 minutes to coagulate and dry, thereby producing a sheet. Next, in the same manner as in Example 1, the sea component (polyethylene) in the sea-island-type mixed spun fiber constituting the nonwoven fabric of the sheet-like material was dissolved and removed, and a 6-nylon ultrafine fiber bundle entangled nonwoven fabric was used. A leather-like sheet in which the composite resin was impregnated and solidified was produced. The attached weight of the composite resin on the leather-like sheet was 59% by weight based on the weight of the nonwoven fabric after the ultrafine fiber treatment. As shown in Table 4, this sheet-like material
It was a natural leather-like sheet having flexibility and a sense of fulfillment, and excellent feeling and durability.

Comparative Example 1 In the same manner as in Example 1, as shown in Table 3, an emulsion having a thermosensitive gelling property was obtained using only MMA as a monofunctional ethylenically unsaturated monomer. Thermal gelation temperature of emulsion, 90 ° C and 160 ° C of film obtained by drying emulsion
Were as shown in Table 4. In the same manner as in Example 1, the nonwoven fabric obtained in Reference Example 1 was impregnated with the above thermosensitive gelling emulsion.
After the application, the sea component (polyethylene) in the sea-island type mixed spun fiber constituting the nonwoven fabric is dissolved and removed.
Composite resin impregnated into nylon ultra-fine fiber bundle entangled non-woven fabric
A solidified leather-like sheet was produced. The attached weight of the composite resin on the leather-like sheet was 58% by weight based on the weight of the nonwoven fabric after the ultrafine fiber treatment. Since the elasticity of the used emulsion at 90 ° C. is higher than the range specified in the present invention, the sheet is inferior in flexibility, and has a resin adhesion weight, flex resistance, flexural rigidity, and feeling. As shown in Table 4.

Comparative Example 2 In the same manner as in Example 1, as shown in Table 3, only BA was used as a monofunctional ethylenically unsaturated monomer to obtain an emulsion having a thermosensitive gelling property. The thermal gelation temperature of the emulsion, the elastic modulus at 90 ° C. and 160 ° C. of the film obtained by drying the emulsion and the α-dispersion temperature were as shown in Table 4. In the same manner as in Example 1, after impregnating and applying the above thermosensitive gelling emulsion to the nonwoven fabric obtained in Reference Example 1, the sea component (polyethylene) in the sea-island type mixed spun fiber constituting the nonwoven fabric was removed. By dissolving and removing, a leather-like sheet in which the composite resin is impregnated and solidified in the 6-nylon ultrafine fiber bundle entangled nonwoven fabric was produced. The attached weight of the composite resin in the leather-like sheet was 57% by weight based on the weight of the nonwoven fabric after the ultrafine fiber treatment. This sheet-like material has an elastic modulus at 160 ° C. of the emulsion used which is lower than the range specified in the present invention, causing sagging, and does not have a paper-like fullness as a whole. The bending resistance, bending stiffness, and hand were as shown in Table 4.

Comparative Example 3 An emulsion was obtained in the same manner as in Example 1, except that Emulgen 109P and calcium chloride were not added. This emulsion did not show heat-sensitive gelling property, and the elastic modulus and α-dispersion temperature at 90 ° C. and 160 ° C. of the film obtained by drying the emulsion were as shown in Table 4.
When the above thermosensitive gelling emulsion was impregnated and applied to the nonwoven fabric obtained in Reference Example 1 in the same manner as in Example 1, the emulsion flowed out into a hot water bath and contaminated the bathtub. Next, in the same manner as in Example 1, the sea component (polyethylene) in the sea-island-type mixed spun fiber constituting the nonwoven fabric of the sheet-like material was dissolved and removed, and a 6-nylon ultrafine fiber bundle entangled nonwoven fabric was used. A leather-like sheet in which the composite resin was impregnated and solidified was produced. The attached weight of the composite resin on the leather-like sheet was 34% by weight based on the weight of the nonwoven fabric after the ultrafine fiber treatment. The sheet-like material was sagged and did not have a paper-like sense of fulfillment as a whole, and the resin adhesion weight, bending resistance, bending rigidity, and hand were as shown in Table 4.
As shown in FIG.

[0088]

[Table 3]

[0089]

[Table 4]

[0090]

According to the production method of the present invention, the use of a fibrous base material composed of ultrafine fibers and the application of a resin with a composite resin emulsion provide a natural leather-like feeling excellent in flexibility and fulfillment. A leather-like sheet can be manufactured at low cost.

Claims (8)

[Claims] 1. A fibrous base material composed of ultrafine fiber-forming fibers is impregnated with a composite resin emulsion satisfying the following conditions (i) to (iv) and solidified, and then the ultrafine fiber-forming fibers are converted to ultrafine fibers. (I) the composite resin emulsion is thermosensitive gelling; (ii) a thickness of 100 μm obtained by drying the composite resin emulsion at 50 ° C. (Iii) elasticity at 160 ° C. of a 100 μm-thick film obtained by drying the composite resin emulsion at 50 ° C. at a temperature of 90 ° C. of 5.0 × 10 ⁸ dyn / cm ² or less; rate is, is 5.0 × 10 ⁶ dyn / cm ² or more; and (iv) the composite resin emulsion is an ethylenically unsaturated monomer in the presence of a polyurethane-based emulsion (a) (B), polyurethane Weight of emissions based emulsion (A) Polyurethane Weight / ethylenically unsaturated monomer in (B) is an emulsion obtained by emulsion polymerization in a proportion of Bu 90 / 10-10 / 90. 2. The α-dispersion temperature of a 100 μm thick film obtained by drying a composite resin emulsion at 50 ° C.
The method for producing a leather-like sheet according to claim 1, wherein the temperature is −10 ° C. or lower. 3. A polyurethane emulsion (A) comprising:
The method for producing a leather-like sheet according to claim 1 or 2, which is a polyurethane emulsion formed by using an aromatic isocyanate compound. 4. The ethylenically unsaturated monomer (B) comprises 90 to 99.9% by weight of a monofunctional ethylenically unsaturated monomer (B1) mainly composed of a (meth) acrylic acid derivative and a polyfunctional ethylenically unsaturated monomer (B1). B2) 10-0.
The method for producing a leather-like sheet according to any one of claims 1 to 3, comprising 1% by weight. 5. A fibrous base material composed of ultrafine fiber-forming fibers is impregnated with a composite resin emulsion satisfying the above conditions (i) to (iv) and solidified, and then the ultrafine fiber-forming fibers are converted into ultrafine fibers. A method for producing a leather-like sheet-like material, wherein the ultrafine fiber-forming fiber is a sea-island composite spun fiber and / or a sea-island mixed spun fiber comprising two or more kinds of polymer substances, and the fiber comprising the fiber The impregnated porous resin base material is impregnated with the composite resin emulsion and coagulated, and then the sea component in the sea-island composite spun fiber and / or the mixed sea-island spun fiber is removed to form an ultrafine fiber. A method for producing a leather-like sheet according to any one of the preceding claims. 6. The sea-island composite spun fiber and / or sea-island mixed spun fiber has polyethylene and / or polystyrene as a sea component and polyester and / or polyamide as an island component, and is used as a fibrous base material. The method according to claim 5, wherein after the impregnation with the composite resin emulsion and coagulation, the sea component in the sea-island composite spun fiber and / or the sea-island mixed spun fiber is dissolved and removed using an organic solvent to form an ultrafine fiber. A method for producing the leather-like sheet according to the above. 7. A composite resin emulsion having a thermal gelation temperature of 30 to 70 ° C., and after impregnating the composite resin emulsion with a fibrous base material, at a temperature 10 ° C. or more higher than the thermal gelation temperature. The method for producing a leather-like sheet according to any one of claims 1 to 6, wherein the composite resin emulsion is coagulated. 8. A leather-like sheet obtained by the method according to any one of claims 1 to 7.