JP2012214945A - Grained artificial leather and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-weight and clear grained artificial leather excellent for surface designability in spite of its thick surface coating and to provide a method of manufacturing the same.SOLUTION: A grained artificial leather comprises: a substrate layer; a first elastic polymer coating layer and a second elastic polymer coating layer that are sequentially coated on a surface of the substrate layer, in which the first elastic polymer coating layer covers a part of circumference of a fiber which composes the surface of the substrate layer, and the second elastic polymer coating layer is gelled with a particle of its composing elastic polymer retaining its particulate state. After portions of the elastic polymer particles are attached to each other, a fine pore with an average diameter of 10 μm or less, which is formed at a gap between the particles, is mixed with a support member with an average diameter of 10 μm to 50 μm.

Description

The present invention relates to a silver-tone artificial leather having a polymer elastic film layer composed of specific fine pores and a method for producing the same. More specifically, the present invention relates to the production of silver-finished artificial leather having good surface smoothness, lightness, and embossing property, and silver-coated artificial leather using an aqueous emulsion resin.

Conventionally, in order to impart smoothness, cushioning properties, physical strength properties and the like to a base material, a film is formed on the surface of the base material. In the past, an organic solvent such as dimethylformamide (DMF) has been used as a solvent in the dispersion applied to the substrate to form a film. However, organic solvents such as DMF are highly flammable and highly toxic. Therefore, there is a risk of fire, and there are concerns about deterioration of the working environment and environmental pollution such as air and water. ing. Moreover, since the organic solvent remains in the film | membrane obtained using the organic solvent, the influence on the human body by touching a film | membrane is also made into a problem. And in order to eliminate such a problem, when the process of collect | recovering a residual organic solvent is integrated, there exists a problem that a lot of disposal cost and labor are applied.

Therefore, artificial leather using an aqueous emulsion resin that does not use an organic solvent has been studied. Patent Document 1 discloses a heat-sensitive coagulable and heat-expandable polyurethane emulsion having a heat-sensitive coagulable polyurethane emulsion and a heat-expandable plastic microballoon as essential components (non-ionic surfactant having a cloud point of 35 to 95 ° C. and 2 to 30 weights). Nonionic polyurethane emulsion having a part as an emulsifier) A method for producing a composition in water or steam at 40 ° C. to 190 ° C. is disclosed. Patent Document 2 discloses a sheet formed from a polymer elastic body, and the sheet has a thickness of 10 to 500 μm and a micropore of 500 to 15,
000 / mm ² , the average pore diameter of the micropores is 1 to 20 μm, and the breaking strength is 1 to
A porous sheet having a breaking elongation of 100 to 500% at 15 N / mm ² is disclosed.
Further, in order to solve the above problems, the applicant of the present invention, the particles of the polymer elastic body are gelled while maintaining the particle state, and after the part is joined, the fine pores formed by the gap between the particles and the average Diameter 1
A base for artificial leather was proposed in which a film mixed with a support member of 0 to 50 μm was laminated on the base material (
Patent Document 3).

Japanese Patent Publication No. 6-60260 Japanese Patent No. 3796573 Japanese Patent Application No. 2010-211202

However, since the production method of Patent Document 1 heat-gelates nonionic polyurethane emulsion, sharp gelation does not appear and it can be applied only to impregnation and thin film coating. There is a problem that the quality deteriorates. Furthermore, since gelation and microcapsule expansion are performed simultaneously, there is a problem that the strength of the film is lowered and a uniform foamed state cannot be obtained. Since the production method of Patent Document 2 uses the cloud point of the water-repellent fine particles, a porous sheet having a low specific gravity cannot be obtained using a urethane emulsion having a high solid content, resulting in poor productivity. .
Moreover, in the nonwoven fabric which has the film obtained by the manufacturing method disclosed in Patent Documents 1 and 2, when the hot water treatment is performed for the ultrafine treatment, the film absorbs the hot water and is damaged or the foam is crushed. It also has the problem that it ends up.
And the base for artificial leather of patent document 3 invention WHEREIN: Furthermore, the silver-tone artificial leather which has design (unevenness pattern) formation property, smoothness, and peeling strength is desired.

The present invention has been made in consideration of the above-mentioned problems, and has a thick surface by disposing a polymer elastic body film having a two-layer structure with good smoothness, lightness and designability on the surface of the base material layer. An object of the present invention is to provide a silver-coated artificial leather capable of realizing an elegant appearance by an excellent design moldability such as being capable of forming a light and clear surface texture while having a film, and a method for producing the same.

The present invention forms a first polymer elastic film layer while arranging a first polymer elastic film layer on the surface of a base material layer containing a polymer elastic body inside a fiber-entangled nonwoven fabric. The polymer elastic body to cover a part of the periphery of the fiber constituting the surface of the base material layer, and the second polymer elastic body coating layer in which a large number of formed micropores and support members are mixed When an artificial leather with silver tone is manufactured by laminating on the surface of the polymer elastic film layer, the second polymer elastic film is applied when the surface is heat-pressed with an embossing roll or the like to give an uneven design. The layer mainly plays a role in forming a concavo-convex pattern, and the first polymer elastic coating layer suppresses the influence of the crushing and thickness of the base material layer due to the hot press and has a peeling strength. Contributing to improvement, using water-based emulsion resin for the film layer, could not be done before, Found that natural leather-graceful appearance and good soft and high peel strength to both grain-finished artificial leather is obtained while amounts, leading to the present invention.

That is, in the present invention, the first polymer elastic film layer and the second polymer elastic film layer are sequentially laminated on the surface of the base material layer containing the polymer elastic material inside the fiber-entangled nonwoven fabric. The first polymer elastic coating layer covers a part of the periphery of the fiber constituting the surface of the base material layer, and the second polymer elastic coating layer is the second polymer elastic coating layer. The average particle diameter formed by the gap between the particles after the particles of the polymer elastic body constituting the layer are gelated while maintaining the particle state and a part of them is joined
A silver-finished artificial leather characterized by a mixture of fine pores of 0 μm or less and a support member having an average diameter of 10 to 50 μm.

Moreover, this invention is a manufacturing method of the silver-tone artificial leather containing the process of following (1)-(3).
(1) On the surface of a base material layer containing a polymer elastic body inside a fiber-entangled nonwoven fabric, (A) a polymer elastic body comprising a hydrophilic functional group-containing resin, (B) an ammonium salt, and (C) A thickener is included, and the mixing ratio of the (A) component and the (B) component is (A) :( B) = 100: 0.
An aqueous dispersion capable of forming a first polymer elastic film layer having a composition of 25 to 100: 10 and a viscosity (η ₆ ) of 200 to 1000 Pa · s is formed around the fibers constituting the surface of the base material layer. A step of forming a first polymer elastic body coating layer by coating so as to partially cover (2) (A) a hydrophilic functional group-containing resin on the surface of the first polymer elastic body coating layer A polymer elastic body, (B) an ammonium salt, (C) a thickener and (D) a support member, and the blending ratio of the component (A) and the component (B) is a mass ratio of the solid content (A) (B) = 100: 0.25-10
Steps (3), (1) and (2) for applying an aqueous dispersion capable of forming a second polymer elastic film layer having a composition of 0:10 and a viscosity (η ₆ ) of 30 to 500 Pa · s A part of the periphery of the fibers constituting the surface of the base material layer is formed by subjecting the aqueous dispersion to be used to heat-gelling sequentially or simultaneously, followed by drying and solidifying, and the polymer elastic body constituting the first polymer elastic body coating layer The particles of the polymer elastic body constituting the first polymer elastic film layer and the second polymer elastic film layer covering the gel are maintained in the state of the particles, and the particles are bonded to each other after being partly bonded. Forming a second polymer elastic film layer in which micropores having an average diameter of 10 μm or less and a support member having an average diameter of 10 to 50 μm formed by the gaps are mixed

The surface of the silver-finished artificial leather of the present invention is excellent in smoothness and design formability, is lightweight and has high peel strength. In particular, even when a thick film layer made of an aqueous emulsion resin is formed, the above effect is obtained.

Hereinafter, the present invention will be described in detail.
First, the base material layer of the present invention comprises a fiber-entangled nonwoven fabric obtained by three-dimensionally intertwining fibers, and a polymer elastic body impregnated therein. The shape of the fibers constituting the base material layer is not particularly limited, but is preferably a hollow fiber for the purpose of achieving both the lightness and the strength, and can be produced by a known method. For example, a fiber that can be made into a hollow fiber by extracting island components from sea-island type multi-component fibers composed of polymers having at least two types of spinning properties with different chemical or physical properties is used. be able to. It is a fiber that can change the fiber form by extracting and removing at least one kind of polymer at an appropriate stage before and after impregnation with the polymer elastic body. This hollow fiber generating fiber can be obtained by a method represented by a chip blend (mixed spinning) method or a composite spinning method. A typical form of the fiber is a so-called sea-island fiber.

Moreover, if it is the objective which makes soft property and a physical property compatible, it is preferable that it is a microfiber (bundle). In the case of using ultrafine fibers (bundles), for example, if the above-mentioned sea-island type multicomponent fiber is used, it can be obtained by extracting and removing sea components as opposed to forming hollow fibers. .

Examples of the polymer constituting the non-extractable component of such sea-island fibers include polyamides that can be melt-spun such as 6-nylon and 66-nylon, polyethylene terephthalate, polybutylene phthalate, isophthalic acid-modified polyester, cationic cation. Examples thereof include at least one polymer selected from melt-spun polyesters such as dye-modified polyethylene terephthalate and polyolefins typified by polypropylene.
In addition, as the component to be extracted and removed, a known component constituting the sea-island fiber can be used, and examples thereof include a component that is composed of a water-soluble polymer component and that can be spun. For example, as the water-soluble polymer component, a known polymer can be used as long as it is a polymer that can be extracted with water or an aqueous solvent, but it is preferable to use polyvinyl alcohol copolymers that are soluble in an aqueous solvent. .
The volume ratio between the sea component and the island component of this sea-island fiber is 1: 2 to 2: 1, and the fineness when the sea component is extracted and made into ultrafine fiber is 0.01 in terms of texture and fulfillment. ~ 0.0001
The range of dtex is good, and the fineness in the case of obtaining a porous hollow fiber after extracting the island component is preferably in the range of 0.5 to 4.0 dtex in terms of texture and fullness.

The entangled nonwoven fabric composed of the sea island fiber may be manufactured by entanglement treatment with a needle punch or a high-speed fluid after making a short fiber web of 20 to 75 mm in length by a card method,
Moreover, after making a continuous fiber web simultaneously with spinning by a direct method such as the spunbond method, it may be manufactured by entanglement with a needle punch or a high-speed fluid.

Next, a fiber entangled nonwoven fabric before and after hollow fiber formation or before and after ultrafine fiber formation is impregnated with a polymer elastic body solution or dispersion to form a base material layer.
In the present invention, the polymer elastic body contained in the fiber-entangled nonwoven fabric may be any one that has been conventionally used in the production of general artificial leather, and a known polymer elastic body can be used. Among them, polyurethane is preferably used in terms of obtaining a natural leather-like texture and physical properties. For example, one or more polymer diols such as polyester diol, polyether diol polyester / ether diol, polycarbonate diol; It is produced from an isocyanate, preferably one or more aliphatic, aromatic or alicyclic organic diisocyanates; and a chain extender having two active hydrogen atoms such as a low molecular diol, a low molecular diamine or hydrazine. And polyurethane.

Next, the first and second polymer elastic film layers formed on the base material layer will be described.
In the silver-tone artificial leather of the present invention, a part of the polymer elastic body forming the first polymer elastic film layer is formed on at least one surface of the base material layer thus obtained. It is important to coat a part of the periphery of the fibers constituting the concavo-convex surface in terms of smoothing the surface of the silver-finished artificial leather and increasing the peel strength. And it is preferable that 60% or more of the periphery of the fiber exposed on the surface of the base material layer is covered by a part of the polymer elastic body forming the first polymer elastic film layer, and 80% or more is covered. It is more preferable. In order to cover 60% or more, the fiber ratio constituting the base material is 70% or more, and the polymer elastic body contained in the base material is made into a water-dispersed polyurethane,
By dry-solidifying, the fibers constituting the substrate surface can be easily exposed on the substrate surface by a combination of forms in which the fiber density is increased and the polymer elastic body is discontinuously present. preferable.
Here, covering a part of the periphery of the fiber is preferably in a state of being adhered or closely adhered to a part of the periphery of the fiber, but with a space around a single fiber or fiber bundle, The polymer elastic body may cover.
And being filled with at least 20 μm or more in the thickness direction from the surface of the base material layer,
It is preferable at the point which improves the said effect.
Regarding the extent to which the polymer elastic body covers a part of the periphery of the fiber constituting the surface of the substrate, a cross section parallel to the thickness direction of the artificial leather with silver was photographed with an electron microscope, and a photograph If any 20 fibers are extracted from the sample and the periphery of the fiber is covered with a polymer elastic body, the ratio can be calculated and averaged.
Polymer elasticity forming the first polymer elastic film layer formed so as to form a smooth surface and filled so as to cover a part of the fiber in the range of 20 μm below the surface of the base material layer. The body sinks into the surface layer of the base material from the time it is applied to the base material layer and solidifies, and at the same time, stays on the surface of the base material layer to form a smooth coating layer on the surface of the base material layer. When the polymer elastic body forming the second polymer elastic film layer is applied, it serves to prevent the polymer elastic body from sinking into the base material layer and Ensure good adhesive strength. Moreover, it has an auxiliary function of forming the surface of the second elastic polymer film layer more smoothly. And it plays the role which ensures sufficient peeling strength between base materials by filling so that a part of fiber near the surface of a base material may be covered. The peel strength of the resulting silver-tone artificial leather is preferably 3 kg / 25 mm or more, more preferably 5 kg / 25 mm or more, and even more preferably 7 kg / 25 mm or more.

[Preparation of aqueous dispersion]
The aqueous dispersion for forming the first polymer elastic film layer contains (A) a polymer elastic body made of a hydrophilic functional group-containing resin, (B) an ammonium salt, and (C) a thickener.
(A) A polymer elastic body comprising a hydrophilic functional group-containing resin (hereinafter sometimes referred to as component (A)) is a self-emulsifying type that can be emulsified without using an anionic or nonionic surfactant. It is an aqueous emulsion resin. Forced emulsification type water-based emulsion resins that require the use of anionic and nonionic surfactants are insensitive to gelation in the thermal gelation process, and film formation after gelation is insufficient. Tend. Therefore, it is necessary to perform heat-sensitive gelation treatment and drying and solidification at a low temperature for a long time, and the production efficiency is extremely poor. In addition, the use of a surfactant has the disadvantages that the physical properties such as the peel strength of the formed film with respect to the substrate are lowered, and the surfactant bleeds on the surface of the film over time and the appearance is impaired.
The self-emulsifying type water-based emulsion resin does not have the above-mentioned problems, and can be subjected to heat-sensitive gelation treatment and drying and solidification at a high temperature. Compared with the case of using a forced emulsification type water-based emulsion resin, Production efficiency is improved.
Moreover, since the film | membrane which consists of a self-emulsification type water-based emulsion resin has the hot water resistance with the low swelling rate with respect to hot water, it can prevent damage | damage of a film | membrane.

The component (A) is a self-emulsifying type water-based emulsion resin, and by itself, it does not gel unless it is at a relatively high temperature (about 90 ° C.), but (B) an ammonium salt (hereinafter referred to as (B) component) Is added at a temperature of about 60 ° C.
In the aqueous dispersion of the present invention, the compounding ratio of the component (A) and the component (B) is (A) :( B) = 100: 0.25 to 100: 10 in terms of solid content. When the blending ratio of the component (B) is less than 0.25, gelation by the thermal gelation treatment is not sufficiently performed, and cracks are generated on the surface of the film. Moreover, when the compounding ratio of (B) component exceeds 10, physical properties, such as peeling strength with respect to the base material of the membrane | film | coat obtained, will fall. Moreover, a fine crack may enter into the film surface. From the viewpoint of sufficiently performing gelation and improving physical properties such as peeling strength of the film, it is preferably in the range of (A) :( B) = 100: 0.5 to 100: 9 in terms of mass of solid content. Yes, more preferably in the range of (A) :( B) = 100: 1 to 100: 7.

The aqueous dispersion of the present invention contains (C) a thickener. (C) By including a thickener, the viscosity of the aqueous dispersion increases, and a uniform and thick film can be formed. The viscosity of the aqueous dispersion is preferably from 200 to 1000 Pa · in terms of viscosity (η ₆ ) measured at 6 rpm with a single cylindrical rotational viscometer from the viewpoint of forming a uniform and thick film. s, more preferably 300 to 700 Pa · s, and even more preferably 35.
The range is 0 to 600 Pa · s. By setting the viscosity of the aqueous dispersion to 200 Pa · s or more, micropores are difficult to develop, and a substantially non-porous layer is easily generated.
In addition, (C) the viscosity of the thickener is applied to the surface of the substrate, and the viscosity immediately after the application is maintained until the thermal gelation treatment is completed, so that the aqueous dispersion sinks into the substrate. It is effective in preventing the coating, and the application state is hardly affected by the type of the substrate. It becomes possible to easily fill at least 20 μm or less in the thickness direction from the surface of the base material layer, and the lower limit is preferably 500
It becomes easy to fill the surface from μm, more preferably from 400 μm, and even more preferably from 300 μm, and the peel strength is easily improved, and the effect of suppressing the generation of cracks on the film surface during drying and solidification is also exhibited.
Here, the components contained in the aqueous dispersion of the present invention will be described.

(A) Examples of the polymer elastic body comprising a hydrophilic functional group-containing resin include hydrophilic functional group-containing aqueous emulsion polyurethane resins, polyacrylic resins, and mixtures of polyurethane resins and polyacrylic resins. it can. Among these, from the viewpoint of flexibility, an aqueous emulsion polyurethane resin containing a hydrophilic functional group is particularly preferable.
(A) A polymer elastic body comprising a hydrophilic functional group-containing resin reacts, for example, with (a) an organic diisocyanate, (b) a polyol, and (c) a compound having a hydrophilic functional group and two or more active hydrogens. The hydrophilic functional group-containing isocyanate group-terminated prepolymer obtained by neutralization is self-emulsified in water and then (d) a chain extension reaction using a chain extender.
(A) As an organic diisocyanate, an aliphatic diisocyanate having two isocyanate groups, an alicyclic diisocyanate, and an aromatic diisocyanate can be used.
Examples of such (a) organic diisocyanate include aliphatic diisocyanate compounds such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, dicyclohexylmethane diisocyanate, norbornane diisocyanate, and 1,3-bis ( Isocyanatomethyl) cyclohexane and other alicyclic diisocyanate compounds, tolylene diisocyanate,
Examples thereof include aromatic diisocyanate compounds such as diphenylmethane diisocyanate, naphthalene diisocyanate, tolidine diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate.
Also, these alkyl-substituted products, alkoxy-substituted products, nitro-substituted products, prepolymer modified products with polyhydric alcohols, carbodiimide modified products, urea modified products, burette modified products,
Dimerization or trimerization reaction products can also be used, and organic diisocyanates other than the above compounds can also be used. These organic diisocyanate compounds can be used individually by 1 type, or can also be used in combination of 2 or more type.
Among these (a) organic diisocyanates, aliphatic diisocyanate compounds and alicyclic diisocyanate compounds are preferred from the viewpoint of yellowing resistance, thermal stability, and light stability of the resulting resin and the film to be formed, Hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, norbornane diisocyanate and 1,3-bis (isocyanatomethyl) cyclohexane are preferred.

(B) The polyol is not particularly limited as long as it has two or more hydroxyl groups. In addition to a polyester polyol, a polycarbonate polyol, a polyether polyol, etc., a polyether ester polyol having an ether bond and an ester bond may also be used. Can be used.
Examples of such polyester polyols include polyethylene adipate, polybutylene adipate, polyethylene butylene adipate, polyhexamethylene isophthalate adipate, polyethylene succinate, polybutylene succinate, polyethylene sebacate, polybutylene sebacate, poly-ε- Caprolactone diol, poly (3-
Methyl-1,5-pentylene) adipate, polycondensate of 1,6-hexanediol and dimer acid, copolycondensate of 1,6-hexanediol, adipic acid and dimer acid, polycondensation of nonanediol and dimer acid And a copolycondensation product of ethylene glycol, adipic acid and dimer acid.
Examples of the polycarbonate polyol include polytetramethylene carbonate diol, polyhexamethylene carbonate diol, poly t-1,4-cyclohexane dimethylene carbonate diol, and 1,6-hexanediol polycarbonate polyol.
Furthermore, as the polyether polyol, for example, polyethylene glycol, polypropylene glycol, polytetramethylene glycol homopolymer, block copolymer, random copolymer, ethylene oxide and propylene oxide, ethylene oxide and butylene oxide random copolymer And a block copolymer.

Moreover, such (b) polyol can be used individually by 1 type, or can also be used in combination of 2 or more type. Furthermore, as an average molecular weight of such (b) polyol, it is preferable that it is 500-5000, and it is more preferable that it is 1000-3000. In addition, from the viewpoint that sufficient durability can be imparted to the substrate by the hydrophilic functional group-containing resin, it is preferable to use a polycarbonate polyol or a polyether polyol as the above-mentioned (b) polyol.

(C) As a compound having a hydrophilic functional group and two or more active hydrogens, for example, 2, 2
-Dimethylol lactic acid, 2,2-dimethylol propionic acid, 2,2-dimethylol butanoic acid, 2,2-dimethylol valeric acid, 3,4-diaminobutanesulfonic acid, 3,6-diamino-2-toluenesulfonic acid , Etc.
Further, as a compound having such a hydrophilic functional group and two or more active hydrogens, a diol having a hydrophilic functional group, an aromatic dicarboxylic acid or an aromatic disulfonic acid, an aliphatic dicarboxylic acid or an aliphatic disulfonic acid It is also possible to use a polyester polyol having a pendant type hydrophilic functional group obtained by reacting with the above. In place of the diol having the hydrophilic functional group, a diol having no hydrophilic functional group may be mixed and reacted as a diol component. In addition, a compound having such a hydrophilic functional group and two or more active hydrogens is
One kind can be used alone, or two or more kinds can be used in combination.
(C) When using the compound which has a hydrophilic functional group and two or more active hydrogens, the acid value of (A) component is 5-50 KOHmg / g, More preferably, it is 10-40 KOHmg.
/ G is preferably used so as to be within the range of / g. If the acid value is 5 KOHmg / g or more,
If the resin has excellent mechanical stability and mixing stability with other components, and the acid value is 50 KOHmg / g or less, an aqueous dispersion having an appropriate viscosity can be prepared, and the water resistance of the resulting film This is also preferable. Here, the acid value is measured by, for example, Japanese Industrial Standard JIS K5400.
According to the method disclosed in the above.

In addition, when producing an isocyanate group-terminated prepolymer by reacting (a) an organic diisocyanate, (b) a polyol, and (c) a compound having a hydrophilic functional group and two or more active hydrogens, if necessary Low molecular weight chain extenders having two or more active hydrogen atoms can be used.
Such a low molecular weight chain extender having two or more active hydrogen atoms has a molecular weight of 40.
It is preferably 0 or less, particularly preferably 300 or less. Such low molecular weight chain extenders include, for example, ethylene glycol, propylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, pentaerythritol, sorbitol and the like. Molecular weight polyhydric alcohols; low molecular weight polyamines such as ethylenediamine, propylenediamine, hexamethylenediamine, diaminocyclohexylmethane, piperazine, 2-methylpiperazine, isophoronediamine, diethylenetriamine, and triethylenetetramine. Further, such a low molecular weight chain extender having two or more active hydrogen atoms can be used alone,
Or it can use combining 2 or more types.
The specific method for producing the hydrophilic functional group-containing isocyanate group-terminated prepolymer is not particularly limited. For example, it may be produced by a conventionally known one-stage so-called one-shot method, multi-stage isocyanate polyaddition reaction method, or the like. Can do. The reaction temperature at this time is 40-15.
It is preferably 0 ° C. In addition, a reaction catalyst such as dibutyltin dilaurate, stannous octoate, dibutyltin-2-ethylhexanoate, triethylamine, triethylenediamine, N-methylmorpholine may be added as necessary during such a reaction. Can do.

Neutralization of the hydrophilic functional group-containing isocyanate group-terminated prepolymer can be carried out using a known method as appropriate before or after the preparation of the hydrophilic functional group-containing isocyanate group-terminated prepolymer. There is no particular limitation on the neutralizing agent used for neutralizing such a hydrophilic functional group-containing isocyanate group-terminated prepolymer, such as trimethylamine, triethylamine, tri-n-propylamine, tributylamine, N-methyl-diethanolamine, N, N-
Examples thereof include amines such as dimethylmonoethanolamine, N, N-diethylmonoethanolamine, and triethanolamine, potassium hydroxide, sodium hydroxide, and ammonia. Among such neutralizing agents, trimethylamine, triethylamine, tri-n
-Tertiary amines having no hydroxyl group such as propylamine and tributylamine are particularly preferred.

Next, as an emulsifying device used for self-emulsification in water after neutralization, there is no particular limitation,
Examples thereof include a homomixer, a homogenizer, and a disper. In addition, the self-emulsification is preferably performed by self-emulsification in water in the temperature range of room temperature to 40 ° C. without using an emulsifier to suppress the reaction between the isocyanate group and water as much as possible. Furthermore, when self-emulsifying in this way, reaction inhibitors such as phosphoric acid, sodium dihydrogen phosphate, disodium hydrogen phosphate, paratoluenesulfonic acid, adipic acid, benzoyl chloride are added as necessary. be able to.

And after making it self-emulsify in water, it is made to carry out chain extension reaction using (d) chain extension agent, and the aqueous dispersion of (A) hydrophilic functional group containing resin can be obtained.
Such (d) chain extender is preferably a polyamine compound having two or more amino groups and / or imino groups, such as ethylenediamine, propylenediamine, tetramethylenediamine, hexamethylenediamine, diaminocyclohexylmethane, piperazine, Diamines such as hydrazine, 2-methylpiperazine, isophoronediamine, norbornanediamine, diaminodiphenylmethane, tolylenediamine, xylylenediamine; diethylenetriamine, triethylenetetramine, tetraethylenepentamine, iminobispropylamine, tris (2-aminoethyl) Polyamines such as amines; amidoamines derived from diprimary amines and monocarboxylic acids; water-soluble amine derivatives such as monoketimines of diprimary amines; oxalic acid dihydrazides Malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, itaconic acid dihydrazide, 1,1'-ethylenehydrazine, 1,1'-trimethylenehydrazine, 1 , 1 '-(1,4-butylene) dihydrazine and the like. These amino groups and / or imino groups are
The polyamine compound which has one or more can be used individually by 1 type, or can also be used in combination of 2 or more type. The chain extension reaction is preferably performed at a reaction temperature of 20 to 40 ° C., and is usually completed in 30 to 120 minutes.

(A) The value of the 100% modulus of the polymer elastic body comprising a hydrophilic functional group-containing resin is preferably 1 to 9 MPa, and more preferably 2 to 6 MPa. 100
If the% modulus value is 1 MPa or more, a film having excellent wear resistance can be formed, and if it is 9 MPa or less, a soft texture film can be obtained. 100
The value of% modulus is measured according to JIS K 6251 (1993), and dumbbell-shaped 3
It is a value of a predetermined elongation tensile stress (MPa) when the distance between the marked lines is increased by 100% (when the distance between the marked lines is increased by a factor of 2) using a test piece having a symbol shape.
Moreover, it is preferable that content of the hydrophilic functional group in (A) hydrophilic functional group containing resin is 0.5-4.0 mass%, and it is 1.0-2.0 mass%. More preferred. If the hydrophilic functional group content is 0.5% by mass or more, the storage stability of the component (A) is good, and if it is 4.0% by mass or less, the thermal gelation temperature is in an appropriate temperature range. It has a sufficient effect of preventing migration.
Furthermore, it is preferable to hold the polymer elastic body made of (A) a hydrophilic functional group-containing resin in a self-emulsified form. The pH value at that time is preferably 7.0 to 9.0, 7.5
More preferably, it is -8.5. If the pH value is 7.0 or more, the storage stability of the component (A) is good, and if the pH is 9.0 or less, there is a sufficient effect of preventing migration.

<(B) Ammonium salt>
Examples of the ammonium salt used in the present invention include ammonium salts such as hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid and carboxylic acid. Examples of the carboxylic acid include saturated fatty acids such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, capric acid, and stearic acid; unsaturated fatty acids such as oleic acid and linoleic acid; benzoic acid, phthalic acid, Aromatic carboxylic acids such as isophthalic acid and terephthalic acid; saturated dicarboxylic acids such as malic acid, citric acid, succinic acid, malonic acid, succinic acid and adipic acid; unsaturated dicarboxylic acids such as fumaric acid and maleic acid; lactic acid and acrylic acid , Polyacrylic acid, polymaleic acid and the like. These ammonium salts can also use what is marketed.
Among the above ammonium salts, it can be easily removed by impregnation of the mixed solution, migration prevention of the component (A) during the drying process, and volatilization during drying or washing with water after drying, and remains in the resulting film. From the viewpoint of being rare, an ammonium sulfate salt or an ammonium salt of a carboxylic acid having 1 to 10 carbon atoms is preferred, and an ammonium sulfate salt or an ammonium salt of a carboxylic acid having 1 to 4 carbon atoms is more preferred.

In the film forming method of the present invention, when the (B) ammonium salt is mixed with the component (A), the component (B) can be mixed in a solid (powder) state. From the viewpoint of maintaining the stability of the emulsion, it is more preferable to dissolve the component (B) in water and mix it with the component (A) in the form of an aqueous solution. At this time, the pH value of the aqueous solution containing (B) ammonium salt is 7.0 to 7.0.
9.0 is preferable, and 7.5 to 8.5 is more preferable. pH value is 7.
If it is 0 or more, the generation of precipitates can be suppressed when mixing with the component (A),
If pH value is 9.0 or less, there exists an effect of sufficient migration prevention of (A) component.

<(C) Thickener>
In general, as thickeners, there are associative thickeners and water-soluble polymer thickeners. Associative thickeners are physically thickened by cross-linking between particles by the interaction between the hydrophobic group of the component to be thickened and the hydrophobic group of the associative thickener. The (C) thickener used in the present invention is the temperature of the aqueous dispersion produced in the process of completing the gelation of the film by the addition of (B) ammonium salt or thermal gelation treatment. Those having little change in thickening effect due to change and pH change are preferably used, and can be selected from associative thickeners and water-soluble polymer thickeners.
The associative thickener used in the present invention includes a urethane-based associative thickener, an associative thickener obtained by copolymerization with other acrylic monomers using a nonionic urethane monomer as an associative monomer, and An associative thickener having an aminoplast skeleton can be mentioned. Among such associative thickeners, from the viewpoint of the fineness of the pores of the porous structure and strength retention, an associative thickener having a polyethylene glycol chain and a urethane bond in the molecular chain is preferable.
As a commercial product, Neo Sticker S (manufactured by Nikka Chemical Co., Ltd.) and the like can be mentioned.
Examples of the water-soluble polymer thickener used in the present invention include cellulose-based, polycarboxylic acid-based, and polymer polysaccharide-based ones. Among them, those having strong nonionic properties (B)
There is little change in the thickening effect due to temperature change and pH change during the addition of ammonium salt or thermal gelation treatment, and high viscosity is easily obtained stably. Commercially available products include HEC AX-15 (manufactured by Sumitomo Seika Co., Ltd., hydroxyethyl cellulose), Aron A-50P (manufactured by Toagosei Co., Ltd., sulfonic acid monomer copolymer acrylic thickener), Kelzan (Sanki Co., Ltd.) And high molecular polysaccharides).
When a film is formed using a water-soluble polymer thickener, the thickener in the film may bleed over time or become sticky due to moisture absorption. Preferably, it is not suitable for forming a general film without a cleaning step after the film is formed.
In addition, these thickeners can be used individually by 1 type, or can also be used in combination of 2 or more type.

(C) The blending amount of the thickener is different between the case where the first polymer elastic film layer is formed and the case where the second polymer elastic film layer is formed. In the body coating layer, (
Preferably it is the range of 0.5-20.0 mass parts with respect to 100 mass parts of solid content of A) component, More preferably, it is the range of 1.0-15 mass parts. (C) If the thickener is 0.5 parts by mass or more, it is possible to increase the viscosity of the aqueous dispersion and remain in a state where a sufficiently thick film can be formed on the surface of the base material layer. An aqueous dispersion having a viscosity in the optimum range for handling can be obtained. By adding a thickener or the like to make the viscosity of the aqueous dispersion liquid 200 Pa · s or more, micropores are hardly developed and a substantially non-porous layer is easily generated.

Next, a second polymer elastic film layer is formed on the surface of the first polymer elastic film layer. This second polymer elastic film layer has a thickness of about 100 to 600 μm, and a relatively thick film as well as a thin film can be obtained. It is possible to select freely. And while having a micropore with an average diameter of 10 micrometers or less, it is 10
By having large pores with an average diameter of ˜50 μm, a low-density second polymer elastic film layer exists. The large holes are derived from the support member, and are preferably 20 μm or more, and more preferably 30 μm or more in that the micropores are not easily crushed.
The micropores play an important role in forming a leather-like pattern on the surface by a subsequent embossing process or the like. That is, the fine holes occupying most of the surface are deformed together with the large holes by the embossing process, so that the target surface design (uneven pattern) pattern can be easily transferred faithfully to the uneven pattern of the embossing roll. In order to easily transfer this pattern, for example, in the cross section of the second polymer elastic film layer, a length of 50 μm below the surface parallel to the thickness direction and 200 μm parallel to the surface. The presence of 10 or more micropores per area surrounded by the length is preferable in that a clear embossed pattern can be formed on the surface, preferably 20 or more, more preferably 30 or more, 50 or more is particularly preferable, and 140 or more is most preferable.

The second polymer elastic body coating layer forms a part of the silver surface layer of the silver-coated artificial leather of the present invention. As described later, it is easy to make a thick resin layer and a low-density layer. Is possible. For this reason, in the present invention, specific micropores are formed in the second polymer elastic body coating layer,
Foamed capsule density of elastic polymer film layer formed by a mix of 0.30~0.70g / cm ³ as a supporting member, preferably 0.35~0.60g / cm ^3, more preferably 0. By maintaining the pressure at 35 to 0.55 g / cm ³ , excellent lightness and design formability are ensured.

In order to form the micropores of the second polymer elastic body coating layer, it is important that the micropores are surely expressed when the second polymer elastic body is gelled. It is important to set the composition and viscosity of the aqueous dispersion forming the second polymer elastic film layer in a specific range.
That is, the viscosity of the aqueous dispersion for forming the second polymer elastic film layer is 30 to 500 P.
a · s. Preferably it is 30-400 Pa.s, More preferably, it is 50-280P.
a. s. When the viscosity is less than 30 Pa · s, the aqueous dispersion for forming the second polymer elastic film layer flows when the coating is applied on the first polymer elastic film layer, It becomes difficult to form a thick layer. On the other hand, if the viscosity is too high, it is difficult to express micropores in the second elastic polymer film layer, which is not preferable. On the other hand, in order for this aqueous dispersion to express the desired fine pores, the solid content concentration of the aqueous dispersion is preferably 25 to 50%, more preferably 27 to 40%, and still more preferably 30 to 34. %, Most preferably 31-33%. By adjusting the solid content concentration within this range, the fine pores at the time of gelation can be more reliably and uniformly expressed in the thickness direction, so that higher lightness can be realized. When the solid content concentration is less than 25%, that is, when the solid content is too small, the density of fine particles contributing to film formation during gelation is low, and a film having sufficient strength cannot be formed. On the other hand, if this ratio exceeds 50%, the density of fine particles contributing to film formation during gelation is too high, forming a dense film layer, making it difficult to develop micropores.
And the 2nd polymer elastic body membrane | film | coat layer which comprises the silver-tone artificial leather of this invention etc. is formed as follows, for example.

[Preparation of aqueous dispersion]
The aqueous dispersion for forming the second polymer elastic film layer includes (A) a polymer elastic body comprising a hydrophilic functional group-containing resin, (B) an ammonium salt, (C) a thickener, and (D ) Including a support member. Moreover, it is preferable that a crosslinking agent ((E) component) and another additive are included as needed. Hereinafter, the components contained in the aqueous dispersion of the present invention will be described.
In addition, (A) a polymer elastic body comprising a hydrophilic functional group-containing resin, (B) an ammonium salt, and (C) a thickener are added to an aqueous dispersion for forming the first polymer elastic body film layer. The same component as the component to be used can be used.
In the aqueous dispersion of the present invention, the compounding ratio of the component (A) and the component (B) is (A) :( B) = 100: 0.25 to 100: 10 in terms of solid content. When the blending ratio of the component (B) is less than 0.25, gelation by the thermal gelation treatment is not sufficiently performed, and cracks are generated on the surface of the film. Moreover, when the compounding ratio of (B) component exceeds 10, physical properties, such as peeling strength with respect to the base material of the membrane | film | coat obtained, will fall. Moreover, a fine crack may enter into the film surface. From the viewpoint of sufficiently performing gelation and improving physical properties such as peeling strength of the film, it is preferably in the range of (A) :( B) = 100: 0.5 to 100: 9 in terms of mass of solid content. Yes, more preferably in the range of (A) :( B) = 100: 1 to 100: 7.

The aqueous dispersion of the present invention contains (C) a thickener. (C) By including a thickener, the viscosity of an aqueous dispersion liquid becomes moderately high, and a uniform and thick film can be formed.
And in the composition of the water dispersion which comprises a 2nd polymeric elastic body membrane | film | coat layer, Preferably it is the range of 0.3-15.0 mass parts with respect to 100 mass parts of solid content of (A) component. More preferably, it is the range of 0.5-10.0 mass parts. (C) If the thickener is 0.3 parts by mass or more, the viscosity of the aqueous dispersion for forming the second polymer elastic film layer is maintained at a necessary level, and a uniform and thick film is formed. It is also possible to suppress the occurrence of cracks on the surface of the film during the drying process. On the other hand, if the thickener is 15.0 parts by mass or less, an aqueous dispersion having a viscosity in an optimum range for handling can be obtained. The viscosity of the aqueous dispersion is 30 to 500 Pa · s in terms of viscosity (η ₆ ) measured at 6 revolutions / minute using a single cylindrical B rotational viscometer from the viewpoint of forming a uniform and thick film. Range, preferably 50-4
00 Pa · s.
If the viscosity of the aqueous dispersion constituting the second polymer elastic film layer is 30 Pa · s or more, the micropores are difficult to collapse, and if it is 500 Pa · s or less, the first polymer elastic film layer is formed. Application on the aqueous dispersion to be formed becomes easy.
Moreover, as an effect by including (C) a thickener, the effect of suppressing generation | occurrence | production of the crack of the film | membrane surface in the case of dry solidification is also show | played.
Further, the viscosity of the thickener (C) is maintained until the heat-sensitive gelation treatment is completed, and the viscosity of the aqueous dispersion constituting the second polymer elastic film layer immediately after coating is maintained. There is an advantage that it is difficult to be affected by a decrease in thickness from application to thermal gelation.
Next, the aqueous dispersion forming the second polymer elastic body coating layer is an aqueous dispersion having the same composition as that of the first polymer elastic body already described, but the solid content concentration or (C) It is important to adjust the viscosity by controlling the addition amount of the thickener and at the same time add the (D) support member.

<(D) Support member>
The (D) support member used in the present invention is not particularly limited as long as it is a member that supports the micropores so that they are not crushed when the micropores are formed. preferable. An already-expanded microcapsule is a shell made of a thermoplastic resin, encapsulated with an organic compound having a specific boiling point as an expander, and encapsulated micro-hollow spheres coated with an aqueous dispersion on a substrate and subjected to a gelation treatment. It is a capsule expanded by heating in the previous stage. The stage before the gelation treatment includes an expansion treatment before the preparation of the aqueous dispersion, and a case where the expansion is completed before the aqueous dispersion is applied to the substrate and the gelation temperature is reached. Examples of this type of capsule include those in which vinylidene chloride / acrylonitrile copolymer is used as a shell and isobutane is encapsulated and encapsulated (for example, Matsumoto Microsphere (registered trademark) Matsumoto resin). Depending on the polymer type, shell thickness, balloon diameter, etc., there are various grades in the form of fine powder or water cake, which can be selected. As described above, this (D) support member not only contributes to the realization of the low density of the second polymer elastic film layer of the present invention, but also has a function of assisting formation of micropores that are manifested by gelation.
(D) The support member is preferably an already expanded microcapsule, and can improve the smoothness, lightness, and design formability of the film. To obtain a surface roughness of 30 μm or less, the diameter is 50
It is preferably not more than μm, more preferably not more than 30 μm.

In addition, the amount of the (D) support member added is preferably about 0.2 to 1.5 times, more preferably 0.5 to 1 in terms of the solid content volume ratio of the component (A) from the balance between lightness and film strength. .0 times.
As described above, the effect of including the support member is that, as described above, when the aqueous dispersion is subjected to a thermal gelation treatment to form a gelled film and then dried and solidified to form a film, There is an advantage that micropores formed by the gaps between the particles can be stably obtained by agglomerating and forming a film while maintaining the particle state. The fine pores formed by the gaps between the particles, without the support member, the particles adhere to each other in the drying process to form a film. The thicker the film, the stronger the degree of film formation, smoothness, lightness, and design formation. Sex is reduced.

The aqueous dispersions constituting the first and second polymer elastic film layers constituting the silver-tone artificial leather of the present invention can contain the following additives.
<(E) Crosslinking agent>
In the aqueous dispersion of the present invention, it reacts with the hydrophilic functional group of the component (A) from the viewpoint of forming a crosslinked structure and improving the durability of the film, and promoting the curing and improving the production efficiency (
E) It is preferable to use a crosslinking agent in combination. (E) As a crosslinking agent, an oxazoline-based crosslinking agent,
An epoxy type crosslinking agent, an isocyanate type crosslinking agent, a carbodiimide type crosslinking agent, etc. are mentioned.
Moreover, such (E) crosslinking agent may be used individually by 1 type, and may be used in combination of 2 or more type.
(E) The content of the crosslinking agent is preferably 1. with respect to 100 parts by mass of the solid content of the component (A).
It is the range of 0-5.0 mass parts, More preferably, it is the range of 1.5-4.0 mass parts.

<(F) Other additives>
In the aqueous dispersion of the present invention, various additives can be used in combination as long as the object of the present invention is not impaired. Examples of additives include pigments, dyes, auxiliary binders, leveling agents, thixotropic agents, antifoaming agents, fillers, foaming agents, antisettling agents, ultraviolet absorbers, antioxidants, thinning agents, wetting agents, Examples thereof include coloring inhibitors. Such an additive may be used individually by 1 type, and may be used in combination of 2 or more type. In addition, as above-mentioned, it is preferable that the aqueous dispersion liquid of this invention does not contain surfactant.
Among the above additives, it is particularly preferable to add a foaming agent. By adding a foaming agent, the foaming ratio (the volume after foaming with respect to the volume of the dispersion) can be easily prepared. As such a foaming agent, a commonly used one can be used.

The amount of water added in the aqueous dispersion of the present invention is appropriately adjusted so that the dispersion has a desired viscosity in order to adjust the solid content and the viscosity. Specifically, first, the aqueous dispersion forming the first polymer elastic film layer is preferably 20 to 1 with respect to 100 parts by mass of the solid content.
It is the range of 50 mass parts, More preferably, it is the range of 25-100 mass parts, More preferably, it is 30-75 mass parts.
On the other hand, for the aqueous dispersion forming the second polymer elastic film layer, the solid content is 100.
Preferably, it is 30 to 250 parts by weight, more preferably 40 to 200 parts by weight, with respect to parts by weight.
More preferably, it is the range of 50-150 mass parts.

[Micropore foaming treatment]
In the film forming method of the present invention, a foamed film having a thickness of 100 to 600 μm can be formed by applying an aqueous dispersion for forming the second polymer elastic film layer to form a film. In the film formation method of the present invention, even if the temperature is increased and the air volume is increased, the occurrence of cracks on the surface of the film can be suppressed, so without reducing the production efficiency by the drying process,
A thick foam film having a thickness of 100 to 600 μm can be formed.

The means for the foaming treatment according to the present invention is carried out only by the fine pores formed by the gaps between the particles obtained by aggregating the supporting member and the elastic polymer particles while maintaining the particle state to form a film. Is preferable for the purpose of foaming uniformity and reducing the surface roughness of the coating surface.
When bubbles are entrained and foamed in the process of adjusting the aqueous dispersion, pinholes with a diameter exceeding 5 μm are generated on the surface of the film, and the surface roughness cannot be reduced to 30 μm or less. Since foaming occurs at random, there is a problem that, when embossing, a depression is caused and the smoothness is deteriorated.
From the above points, before applying the aqueous dispersion to the substrate and forming a film, the aqueous dispersion is degassed under reduced pressure,
It is preferable to defoam by a method such as pressure defoaming.

[Application of aqueous dispersion]
The method for forming the coating film by applying the aqueous dispersion of the present invention is not particularly limited, but for example, dip coating, blade coater, air knife coater, rod coater,
A hydro bar coater, a transfer roll coater, a reverse coater, a gravure coater, a die coater, a curtain coater, a spray coater, a roll coater, a cast coater, a screen coater, and the like can be mentioned.
The aqueous dispersion is applied by using these methods. As described above, the first polymer elastic film layer described above is formed on the base material layer, and a specific fine particle is formed on the surface portion. A second polymer elastic film layer that expresses pores is formed. When these first polymer elastic film layers are formed, they may be applied directly after impregnation or once dried. It may be applied again later. Similarly, the second polymer elastic film layer may be applied continuously as it is after the first polymer elastic film layer is formed, or may be applied after drying once again. .

[Thermal gelation treatment]
Each coating applied in the previous step is subjected to thermal gelation treatment at the same time or separately to form a gelled film. By performing heat-sensitive gelation and forming a gelled film, the occurrence of cracks and the like can be suppressed as compared to the case where moisture is evaporated by drying without gelation. The heat-sensitive coagulation temperature at which the coating film gels is preferably 30 to 80 ° C, and more preferably 40 to 70 ° C. Here, the thermal coagulation temperature means that 50 g of the aqueous dispersion is placed in a 100 mL glass beaker, and the beaker is gradually heated in a hot water bath at 95 ° C. while stirring the contents, so that the contents are fluid. It is the temperature when solidifying by losing. If the heat-sensitive coagulation temperature is 30 ° C. or higher, it is possible to prevent the dispersion from gelling in the summer atmosphere, and if it is 80 ° C. or lower, the heat-sensitive gelation is sharply expressed. Therefore, the migration prevention property can be sufficiently exhibited in the next drying step.

Examples of the heat-sensitive gelling treatment include a wet heat treatment and a heat treatment using infrared rays. In particular, wet heat treatment with steam is preferable from the viewpoint of obtaining a good gelled state. Wet heat treatment with steam can be processed if the steam temperature is equal to or higher than the thermal coagulation temperature of the aqueous dispersion. However, in order to achieve more stable production, the temperature should be set to "thermal coagulation temperature + 10 ° C" or higher. Specifically, 40 to 140 ° C is preferable, and 60 to 120 ° C is more preferable.
Moreover, the humidity at the time of performing the wet heat treatment with steam is preferable because drying from the surface is suppressed as it approaches 100%. The steam treatment time is preferably 5 seconds to 30 minutes, more preferably 10 seconds to 20 minutes, from the viewpoint of sufficiently forming a gelled film.
In addition, the wet heat treatment with steam and other methods can be used in combination. Other methods include
For example, solidification methods such as infrared rays, electromagnetic waves, and high frequencies can be mentioned.

[Dry solidification]
The gelled film obtained by the heat-sensitive gelation treatment in the previous step is dried and solidified to form a film. Examples of the drying and solidification method include drying methods such as hot air heating, infrared heating, electromagnetic wave heating, high-frequency heating, and cylinder heating. Among these methods, hot air drying is preferable from the viewpoint of running cost and continuous productivity. In addition, these drying methods can be used individually by 1 type, or can also be used in combination of 2 or more type.
The drying temperature is preferably 60 to 190 ° C., more preferably 80 to 150 ° C. from the viewpoint that the formed film does not deteriorate due to heat and can be sufficiently dried, and from the viewpoint of improving the drying efficiency. is there. The treatment time is preferably 1 to 20 minutes and more preferably 2 to 5 minutes from the viewpoint of sufficient drying and productivity.

[Hot water extraction process]
In the present invention, when a non-woven fabric made of hot water extraction type sea-island fibers is used as a base material, even if an aqueous dispersion is applied to the non-woven fabric previously subjected to the hot water extraction treatment, after forming a film on the non-woven fabric It is also possible to perform a hot water extraction process. And it can be set as the fiber entangled nonwoven fabric which consists of a microfiber (bundle), or the fiber entangled nonwoven fabric which consists of a (porous) hollow fiber.
The specific hot water extraction treatment method is not particularly limited, and a known method can be employed. For example, the extraction component in the nonwoven fabric is dissolved and removed with hot water or a solvent. Extraction of the extracted component with hot water can also be performed according to known methods and conditions conventionally employed in the production of artificial leather and the like.

[Finish (gravure processing / embossing)]
As described above, in the silver-finished artificial leather of the present invention in which the first and second polymer elastic body coating layers are formed on a base material impregnated with a polymer elastic body in a nonwoven fabric, by performing a finishing treatment, The silver-coated artificial leather of the present invention having a natural leather-like appearance is obtained. This is a method for forming a colored layer by applying an ink composed of a colorant such as a pigment and a dye and a known finishing resin to the surface of the silver-finished artificial leather of the present invention by a method such as gravure roll, reverse roll or screen. However, it can be obtained by embossing a natural leather-like texture pattern. The thickness of the colored layer is 20
After forming a colored layer which is preferably not more than μm, an uneven pattern can be imparted to the surface to produce the silver-finished artificial leather of the present invention.
In particular, in order to make this surface have a natural appearance of natural leather, a natural leather-like texture pattern is imparted to the surface by heat and pressure treatment with an embossing roll or the like. The design forming effect of the present invention can be exhibited by the fact that the second elastic polymer coating layer is formed smoothly and that micropores are expressed in this layer. That is, since the surface of the second elastic polymer film layer is smooth, when the natural shallow wrinkle is transferred, this is surely transferred, so that a clear and elegant wrinkle can be formed. In addition, since the water-based polyurethane forming the second polymer elastic film layer is generally difficult to be thermally deformed, the second polymer elastic film layer is formed into a dense film having no micropores. If the fiber is made of general-purpose resin, it is difficult to form a texture due to heat and pressure treatment of the embossing roll unless the fiber is melted or deteriorated by heat. In the present invention, by forming specific micropores in the second polymer elastic film layer, when heated and pressed at a temperature lower than a high temperature that promotes the above-described degradation, a collection of minute thin walls A thin wall of a specific micropore that is a body is deformed, and permanent distortion is generated as it is, so that a clear texture can be transferred. At the same time, the heat and pressure applied during the embossing process also deforms the already expanded microcapsules that form giant pores, and as a result, a desired texture is transferred to the coating layer.

In order to give a natural leather-like design appearance by embossing, the heating temperature of the embossing roll is preferably 100 to 230 ° C. Within the above range, a uniform leather-like texture pattern is imparted to the surface, and the polymer elastic body in the base layer is difficult to thermally deform, which is preferable. The press pressure of the embossing roll is preferably in the range of 0.5 to 15 kg / cm ² . Within the above range, a uniform wrinkle pattern is formed, and the texture can be avoided from becoming hard, which is preferable. Since the obtained silver-finished artificial leather combines softness, flexibility, lightness and natural leather-like appearance, it is more preferable that the heating temperature is 120 to 190 ° C. and the press pressure is 1 to 6 kg / cm ² . The silver-tone artificial leather thus obtained has a natural leather-like textured texture, a high-grade appearance, excellent softness, flexibility, lightness, and a sense of fulfillment.
Example

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by this Example.

Manufacture of nonwoven fabrics Polypropylene (Prime Polypro Y-2005GP manufactured by Prime Polymer Co., Ltd., melting point 16
2 ° C., MFR measured by M method of JIS K7210: 20) as a sea component, water-soluble thermoplastic PVA (Exeval CP-4104MI manufactured by Kuraray Co., Ltd., melting point 209 ° C., JIS K7
The mass of the sea component / island component is determined by using a melt compound spinning die having MFR of 80 measured by the M method of 210) as the island component and 12 islands per sea-island type multicomponent fiber. Ratio 50/5
It was discharged from the die at 240 ° C. so as to be 0. Discharge from the die by adjusting the air in the air jet suction device installed directly below the die so that the spinning speed obtained indirectly from the ratio of the discharge amount per unit time and the fineness of the obtained long fibers is 2500 m / min. The resulting polymer was cooled while being indexed to spin a polyolefin hollow fiber generating composite fiber having an average fineness of 2.82 dtex. PVA of the resulting polyolefin hollow fiber generating composite fiber
The wall thickness separating the two was 1.24 μm. The composite fiber is continuously collected on a mobile net installed directly under the suction device, and then a linear pressure of 17 kg /
A composite fiber web having a basis weight of 44 g / m ² was obtained by pressing in cm.

The composite fiber web was uniformly applied to the web surface using a spray while overlapping the composite fiber web so as to have a basis weight equivalent to 8 webs. Next, using a 1-barb felt needle with a distance of 5 mm from the tip of the needle to the barb, needle punching is alternately performed on both sides of the web with the setting so that the tip of the needle stabbed into the composite fiber web protrudes up to 10 mm from the opposite side. Went. The total number of pierced needles is 1200 / cm
^By performing the needle punching process so as to be ² and entangle the composite fibers,
A fiber-entangled nonwoven fabric having a basis weight of 250 g / m ² was obtained. This nonwoven fabric was heated with hot air at 140 ° C. in a dryer to soften the sea component polypropylene, and immediately pressed between metal rolls with a smooth surface at 145 ° C., thickness 1.4 mm, density A fiber-entangled nonwoven fabric having a smooth surface at 0.18 g / cm ³ was obtained.

A fiber-entangled nonwoven fabric having a smooth surface was impregnated with a water-based polyurethane emulsion having a solid content concentration of 16% by mass, and then dried with hot air at 100 ° C. in a dryer to contain a polymer elastic body. Next, in hot water at 95 ° C. containing 0.5 g / L of HLB9, a nonionic surfactant with a cloud point of 57 ° C. (Sunmall BK-90NM manufactured by Nikka Chemical Co., Ltd.), a hot water immersion time of 20 minutes The island component PVA was dissolved and removed from the composite fiber in the fiber-entangled nonwoven fabric by the dip × nip method. The extraction rate is 91%, and the resultant is an artificial leather made of polyurethane hollow fiber entangled nonwoven fabric and polyurethane having a thickness of 1.10 mm, a basis weight of 209 g / m ² and having 12 hollow portions in the cross section. A base material layer was obtained. The mass ratio of the polypropylene hollow fiber and the polyurethane in the substrate was polypropylene hollow fiber / polyurethane = 73.7 / 26.3. This base material for artificial leather had higher peel strength as the base fabric was cut at the time of peel strength measurement, with a tear strength of 2.7 kg and an apparent density of 0.19 g / cm ³ .

Next, as an aqueous dispersion for forming the first polymer elastic film layer, (A) an aqueous emulsion of a carboxyl group-containing self-emulsifying polyurethane resin (polycarbonate, up to 90 ° C. alone does not thermally gel, but ammonium sulfate Is added, and gels at 60 ° C.) 250 parts by mass (of which the solid content is 100 parts by mass), (B) 5 parts by mass of ammonium sulfate, (C) thickener (trade name: Kelzan, manufactured by Sanki Co., Ltd.) ) A liquid obtained by mixing 3.5 parts by mass with 45 parts by mass of water, and (E) a crosslinking agent (trade name: NK Assist CI, manufactured by Nikka Chemical Co., Ltd.) 3.8 parts by mass with a viscosity of 460 Pa · s. A dispersion was prepared. This aqueous dispersion was degassed under reduced pressure to remove the air bubbles entrained in the preparation process, and then applied to the artificial leather base material created earlier by direct coating (clearance 0 mm) to a thickness of 50 μm. A part of the layer was infiltrated to form a coating film. Next, this coating film was subjected to a heat-sensitive gelation treatment with 90 ° C. steam at a relative humidity of 60% for 10 minutes to obtain a gelled film. Thereafter, it was dried with hot air at 150 ° C. for 10 minutes, and the gelled film was dried and solidified to form a film. In addition, neither a crack nor a pinhole existed on the film | membrane surface, and the uniform surface was obtained.
This coating has a substantially non-porous film-like layer having a thickness of about 13 microns on the surface of the base layer and sinks from the surface of the base layer to about 90 microns in the thickness direction. The first polymer elastic film layer was formed so as to cover the periphery of the fibers constituting the surface of the base material layer.
On top of this, 250 parts by weight of (A) an aqueous emulsion of a carboxyl group-containing self-emulsifying polyurethane resin (polycarbonate, not thermally gelled alone up to 90 ° C, but gelled at 60 ° C when ammonium sulfate is added). (Of which solid content is 100 parts by mass), (B) 5 parts by mass of ammonium sulfate, (C) Thickener (trade name: Kelzan, manufactured by Sanki Co., Ltd.) 1.8 parts by mass is mixed with 70 parts by mass of water. (D) Pre-expanded microcapsules with a particle size of 30 μm (trade name: Matsumoto Microsphere F-80SDE made by Matsumoto Yushi) 11.5 parts by mass (expansion ratio of about 1.6), and (E) cross-linking agent (trade name) : NK Assist CI, manufactured by Nikka Chemical Co., Ltd.) An aqueous dispersion having a viscosity of 120 Pa · s containing 3.8 parts by mass was prepared. This aqueous dispersion was degassed under reduced pressure to remove bubbles entrained in the preparation process, and then applied to the surface of the first polymer elastic film layer that had already been formed to a thickness of 789 μm by direct coating. A second polymer elastic film layer was formed.
Next, a heat-sensitive gelation treatment with 90 ° C. steam at a relative humidity of 60% was performed for 10 minutes to obtain a gelled film. Then, it dried with hot air at 150 degreeC for 10 minute (s), the gelled film was dried and solidified, and the artificial leather which has a micropore in the 2nd polymer elastic body membrane | film | coat layer was obtained. In addition, neither a crack nor a pinhole existed on the foamed film surface, and a uniform surface was obtained.

And as a finish, the polyurethane liquid containing a brown pigment was apply | coated with the gravure roll on the 2nd polymeric elastic body film layer, and the film layer of 5 g / m < ² > was formed.

(1) Evaluation of emboss transferability Using an emboss roll with a roll diameter of 40 cm, a surface temperature of 160 ° C. and a linear pressure of 10 kg / cm
The transfer state of the embossed texture after processing at a processing speed of 1 m / min was visually determined. As the embossing roll, an embossing roll (a) capable of transferring pores having a convex part height of 45 μm and a diameter of 20 μm, and an embossing roll capable of transferring a concave and convex pattern having a convex part height of 200 μm and a diameter of 2 mm ( b) was used.
The embossability of the silver-tone artificial leather of Example 1 determined by the above method was determined by the embossing roll (
Both a) and (b) were good.

(2) Measurement of the thickness of the elastic polymer coating layer and the average diameter and number of micropores in the cross-section of the coating. Five locations were shot in a field of view with a width of about 1 mm. The average value of the thicknesses measured for each was taken as the thickness of the film.
The thickness of the second polymer elastic coating layer in Example 1 measured by the above method was 380 μm.
m.
In addition, the cross section in the thickness direction of the polymer elastic film layer is enlarged to about 1000 to 2000 times with an electron microscope to confirm the presence or absence of micropores, and 50 μm in the thickness direction of the second polymer elastic film layer. The average diameter of the fine holes was determined by dividing the number of fine holes in the range surrounded by the orthogonal direction of 200 μm and the diameter of the corresponding fine holes by the number. In addition, the average pore diameter of the giant pores of the fine pores was defined as the average pore diameter of the average value of the top 50 major diameters.
As a result of observation by the above method, an average pore diameter of 5.4 μm and a thickness of 50 μm are formed around the large pores.
A large number of 84 micropores in the range surrounded by 200 μm in the direction orthogonal thereto was confirmed, and the average pore diameter of the giant pores of Example 1 measured by the above method was 37 μm.

(3) Measurement of the diameter of the opening on the surface of the elastic polymer film layer The surface of the obtained film was magnified about 1000 to 2000 times with an electron microscope, and the area of 50 openings was converted to the area of a circle. Thereafter, the average value of the diameter of the circle was taken as the diameter of the opening.
The diameter of the opening on the surface of the second elastic polymer coating layer in Example 1 measured by the above method was 3.1 μm.

(4) Measurement of the density of the polymer elastic film layer The aqueous dispersion was applied onto the nonwoven fabric, and the solid content after drying was divided by the thickness of the second film layer measured in (2). Density.
The density of the second elastic polymer coating layer in Example 1 measured by the above method was 0.48.
g / cm ³ .

(5) Measurement of surface roughness of polymer elastic film layer Using a white interference microscope (New View 6000) manufactured by Zygo, objective lens: 2
. The surface roughness (maximum height Rz) was measured 5 times with a measurement range of 2.82 mm × 2.13 mm.
The surface roughness of the second elastic polymer coating layer of Example 1 measured by the above method was 20 μm.

(6) Measurement of the ratio of the large pores having a diameter exceeding 75 μm with respect to the total area of the second polymer elastic film layer cross section The cross section in the thickness direction of the obtained film was magnified about 100 times with an electron microscope and the width was 1 mm. Five locations were shot with a field of view. After the film portion in each field of view was cut and the weight was measured, the portion exceeding the diameter of 75 μm was cut and the weight was measured to determine the proportion of the large pores exceeding the diameter of 75 μm.
The ratio of the large pores having a diameter of 75 μm to the total area of the film cross section of the second polymer elastic film layer of Example 1 measured by the above method was 6%.

(7) Measurement of peel strength Lightly scraping the surface of a polyurethane rubber plate 15 cm long, 2.5 cm wide and 5 mm thick with sandpaper, and extending a two-component cross-linking type polyurethane adhesive from either end It is applied uniformly over a range of about 10 cm, while the artificial leather with silver is 25 cm long and 2.5 c wide
Similarly, the test piece cut into m was bonded with an adhesive uniformly applied in a range of about 10 cm in length from either end so that the ends to which the adhesive was applied overlapped. The bonded specimen and rubber plate were pressed at a pressure of about ² to 4 kg / cm ² and then left at 25 ° C. for one day. The edge of each of the test piece and the rubber plate where the adhesive is not applied is the initial interval 5c.
The peel strength of the bonded portion between the rubber plate and the test piece corresponding to the tensile time at a tensile speed of 10 cm / min was measured and recorded on a chart, sandwiched between the upper and lower chucks of the tensile tester set at m. The average value of the portions where the peel strength in the tensile time-peel strength curve obtained on the chart was almost constant was read and taken as the peel strength value of the test piece. A value obtained by arithmetically averaging the peel strength measurement values of three test pieces cut out from any three locations for one type of silver-tone artificial leather was defined as the peel strength value of the silver-tone artificial leather.
The peel strength of the film of Example 1 measured by the above method was 73 N / 2.5 cm.

The silver-finished artificial leather of Example 1 is coated with the first polymer elastic body coating layer so as to cover 80% or more of the fibers near the surface of the base material layer, and the fibers on the surface are polymer elastic. Covering the surface irregularities of the base material by forming a thin, substantially non-porous film layer on the base material layer, ensuring smoothness as a silvered artificial leather, and high peeling Strength was obtained. Also,
By adding a foamed capsule to the second polymer elastic film layer, it becomes possible to have a large number of micropores in the entire second polymer elastic film layer, and the diameter of the micropore opening on the surface. And the surface roughness was improved, and good transferability was ensured for the embossed pattern as described above.

Example 2
By changing the addition ratio of the thickener to 285 Pa · s by changing the addition ratio of the thickener, the viscosity of the aqueous dispersion when forming the first polymer elastic film layer is lower than that of Example 1, so that this layer is more A silver-tone artificial leather of Example 2 was obtained in the same manner as in Example 1 except that the base layer was penetrated deeply. Details are shown in Table 1. Although the layer on the substrate surface of the first polymer elastic coating layer was thinned to a level that cannot express a clear thickness due to the penetration of the aqueous dispersion forming the first polymer elastic coating layer, Similar to 1, mainly covers the fiber near the surface layer, holds the fiber on the surface, and forms a thin resin layer to ensure surface smoothness as a silver-tone artificial leather and high peel strength. Obtained. In addition, by adding a foamed capsule to the second polymer elastic film layer, it becomes possible to have a large number of micropores in the entire second polymer elastic film layer, and the micropore openings on the surface As a result, the surface roughness was improved, and good transferability was ensured for the embossed pattern as in Example 1.

Example 3
The viscosity of the aqueous dispersion at the time of forming the first elastic polymer film layer was changed to 640 Pa · s by changing the addition ratio of the thickener, and the viscosity was higher than that of Example 1 and the clearance during coating was 0.
In the same manner as in Example 1 except that the first polymer elastic body coating layer stays on the surface layer of the base material by submerging in the surface layer portion of the base material layer. It was. Details are shown in Table 1. The obtained artificial leather with silver tone was unevenly distributed and filled in the surface layer portion of the base material rather than the first polymer elastic film layer of Example 1. And the same high peel strength as Example 1 and the favorable transferability with respect to the embossing pattern were ensured.

Example 4
When forming the first polymer elastic film layer, the clearance is 0.2 mm compared to Example 1.
An artificial leather with a silver tone was obtained in the same manner as in Example 1 except that it was spread and applied in a state in which sinking was suppressed. Details are shown in Table 1. The obtained silver-tone artificial leather secured the same high peel strength as in Example 1 and good transferability to the embossed pattern.

Example 5
A silver-tone artificial leather was prepared in the same manner as in Example 4 except that the viscosity of the aqueous dispersion at the time of forming the first polymer elastic film layer was changed to a higher viscosity by changing the addition amount of the thickener. Obtained. Table 1 for details
Shown in The obtained silver-tone artificial leather secured the same high peel strength as in Examples 1 and 4 and good transferability to the embossed pattern.

Example 6
Same as Example 1 except that the coating clearance of the aqueous dispersion at the time of forming the second polymer elastic film layer is made wider than that of Example 1 to make the second polymer elastic film layer thicker. The artificial leather with silver tone was obtained by this method. The obtained silver-finished artificial leather secured high peel strength and good transferability as in Example 1.

Example 7
In the same manner as in Example 1, except that the second polymer elastic film layer was thinned by narrowing the application clearance of the aqueous dispersion forming the second polymer elastic film layer. Got leather. The obtained silver-finished artificial leather secured high peel strength and good transferability as in Example 1.

Example 8
A silver-coated artificial leather was obtained in the same manner as in Example 1 except that the viscosity at the time of application of the aqueous dispersion forming the second polymer elastic film layer was increased. In the obtained artificial leather with silver, the second polymer elastic film layer was thin, and the fine pores that appeared were unevenly distributed near the surface of the second polymer elastic film layer. As well as, high peel strength and good transferability were secured.

Example 9
A silver-tone artificial leather was obtained in the same manner as in Example 8, except that the viscosity at the time of application of the aqueous dispersion forming the second polymer elastic film layer was made higher than that in Example 8. In the obtained silver-tone artificial leather, the second polymer elastic film layer is thinner than Example 8, and the fine pores that appear are concentrated near the surface of the second polymer elastic film layer. However, as in Examples 1 and 8, high peel strength and good transferability were ensured.

Example 10
A silver-tone artificial leather was obtained in the same manner as in Example 1 except that the viscosity at the time of application of the aqueous dispersion forming the second polymer elastic film layer formation was lowered. The obtained silver-tone artificial leather secured high peel strength and good transferability in the same manner as in Example 1.

Comparative Example 1
A synthetic leather with a silver tone was obtained in the same manner except that the foaming treatment of the second polymer elastic film layer was performed by mechanical foaming instead of the support member (already foamed capsule). The obtained silver-finished artificial leather has no large pores with an average particle size of 10 μm or less in the second polymer elastic coating layer, and has large and large proportions of pores formed by connecting the foamed pores. Therefore, the surface smoothness was inferior and the emboss transferability was inferior.

The silver-finished artificial leather of the present invention is suitable for uses such as interior materials for vehicles, furniture, clothing, shoes, bags, bags, sandals, miscellaneous goods and the like.

Claims (7)

The first polymer elastic film layer and the second polymer elastic film layer are sequentially laminated on the surface of the base material layer containing the polymer elastic material inside the fiber-entangled nonwoven fabric, The polymer elastic body coating layer covers a part of the periphery of the fiber constituting the surface of the base material layer, and the second polymer elastic body coating layer is a polymer constituting the second polymer elastic body coating layer. Elastic particles are gelled while maintaining their particle state,
A silver-finished artificial leather, characterized by a mixture of fine pores having an average diameter of 10 μm or less and a support member having an average diameter of 10 to 50 μm, which are formed by a gap between particles after part of them are joined. The part of the polymer elastic body constituting the first polymer elastic film layer is filled with at least 20 μm or more in the thickness direction from the surface of the base material layer in a substantially non-porous state. Silver-tone artificial leather. The second polymer elastic film layer has a thickness of 100 to 600 μm and a density of 0.30 to 0.70 g /
^3. The silver-finished artificial leather according to claim 1, wherein the diameter of the opening of the micropores on the surface is 5 μm or less and the surface roughness is 30 μm or less. The polymer elastic body forming the first polymer elastic film layer and the second polymer elastic film layer is a water-based emulsion polyurethane resin containing a hydrophilic functional group. The artificial leather with a silver tone according to Item. 5. The proportion of large pores having a diameter of more than 75 μm with respect to the total area of the film cross-section parallel to the thickness direction of the second polymer elastic film layer is less than 10%. Silver-like artificial leather. A colored layer having a thickness of 20 µm or less is formed on the surface of the second polymer elastic body film of the silver-tone artificial leather according to any one of claims 1 to 5, and an uneven pattern is further provided on the surface. Silver-like artificial leather. The manufacturing method of the artificial leather with a silver tone including the process of following (1)-(3).
(1) On the surface of a base material layer containing a polymer elastic body inside a fiber-entangled nonwoven fabric, (A) a polymer elastic body comprising a hydrophilic functional group-containing resin, (B) an ammonium salt, and (C) A thickener is included, and the mixing ratio of the (A) component and the (B) component is (A) :( B) = 100: 0.
An aqueous dispersion capable of forming a first polymer elastic film layer having a composition of 25 to 100: 10 and a viscosity (η ₆ ) of 200 to 1000 Pa · s is formed around the fibers constituting the surface of the base material layer. A step of forming a first polymer elastic body coating layer by coating so as to partially cover (2) (A) a hydrophilic functional group-containing resin on the surface of the first polymer elastic body coating layer A polymer elastic body, (B) an ammonium salt, (C) a thickener and (D) a support member, and the blending ratio of the component (A) and the component (B) is a mass ratio of the solid content (A): (B) = 100: 0.25-10
Steps (3), (1) and (2) for applying an aqueous dispersion capable of forming a second polymer elastic film layer having a composition of 0:10 and a viscosity (η ₆ ) of 30 to 500 Pa · s A part of the periphery of the fibers constituting the surface of the base material layer is formed by subjecting the aqueous dispersion to be used to heat-gelling sequentially or simultaneously, followed by drying and solidifying, and the polymer elastic body constituting the first polymer elastic body coating layer The particles of the polymer elastic body constituting the first polymer elastic film layer and the second polymer elastic film layer covering the gel are maintained in the state of the particles, and the particles are bonded to each other after being partly bonded. Forming a second polymer elastic film layer in which micropores having an average diameter of 10 μm or less and a support member having an average diameter of 10 to 50 μm formed by the gaps are mixed