TW202031968A - Synthetic leather - Google Patents

Abstract

The present invention provides a synthetic leather having at least a base fabric (i), an intermediate layer (ii), and a skin layer (iii) and being characterized in that the intermediate layer (ii) is formed from a moisture-curing-type hot-melt urethane resin composition containing a foaming agent composition (A2) and a hot-melt urethane prepolymer (A1) having an isocyanate group, and that the skin layer (iii) is formed from a urethane resin composition containing water (Y) and an anionic urethane resin (X) having an anionic group at a concentration of 0.15 mmol/g or less. The foaming agent composition (A2) preferably contains N,N'-dinitrosopentamethylenetetramine and urea.

Description

Synthetic leather

The present invention relates to synthetic leather.

Polyurethane resin is widely used in the manufacture of synthetic leather (including artificial leather) due to its mechanical strength and good texture. For this purpose, the mainstream solvent-based urethane resin containing N,N-dimethylformamide (DMF) has so far been the mainstream. However, in the context of the European DMF restrictions, the strengthening of VOC emission restrictions in China and Taiwan, and the DMF restrictions of large-scale apparel manufacturers, it is required to remove DMF from the urethane resin used in each layer of synthetic leather.化.

In order to respond to such an environment, we are extensively reviewing the use of aqueous urethane resin compositions in which urethane resins are dispersed in water and solvent-free moisture-curing hot-melt urethane resins (e.g. Refer to Patent Document 1). However, the actual situation is that there is no synthetic leather that uses environmentally compatible materials for both the middle layer and the skin layer, and has both hydrolysis resistance, chemical resistance, and texture. [Prior Technical Literature] [Patent Literature]

Patent Document 1 　 JP 2007-119749 A

[Problem to be solved by the present invention]

The problem to be solved by the present invention is to provide a synthetic leather that is excellent in hydrolysis resistance, chemical resistance, and texture. [Means used to solve the problem]

The present invention provides a synthetic leather, which is a synthetic leather having at least a base cloth (i), an intermediate layer (ii), and a skin layer (iii), characterized in that: the intermediate layer (ii) is composed of an isocyanate group The hot-melt urethane prepolymer (A1) and the moisture-curing hot-melt urethane resin composition of the blowing agent composition (A2) are formed, and the aforementioned skin layer (iii) is composed of A urethane resin composition containing an anionic urethane resin (X) having an anionic group concentration of 0.15 mmol/g or less and water (Y). [Effects of the invention]

In the synthetic leather of the present invention, since the middle layer is formed of a solvent-free moisture-curing hot-melt urethane resin composition, and the skin layer is formed of a water-containing urethane resin composition, It is excellent in environmental response, hydrolysis resistance, chemical resistance, and texture.

Therefore, the synthetic leather of the present invention can be used in applications requiring high durability, such as automotive interior materials, furniture, and sports shoes, where it is difficult to replace solvent-based to water-based•solvent-free systems.

[Form for implementing invention]

The synthetic leather of the present invention is a synthetic leather having at least a base cloth (i), an intermediate layer (ii), and a skin layer (iii). The intermediate layer (ii) is composed of a hot-melt urethane containing isocyanate groups. The prepolymer (A1) and the foaming agent composition (A2) are formed of a moisture-curing hot-melt urethane resin composition, and the aforementioned skin layer (iii) is composed of anionic groups at a concentration of It is formed of an anionic urethane resin (X) of 0.15 mmol/g or less and a urethane resin composition of water (Y).

As the aforementioned base fabric (i), for example, polyester fibers, polyethylene fibers, nylon fibers, acrylic fibers, polyurethane fibers, acetate fibers, rayon fibers, polylactic acid fibers, cotton, Non-woven fabrics, woven fabrics, knitted fabrics, etc. made of hemp, silk, wool, glass fiber, carbon fiber, and blended fibers of these. In addition, as the aforementioned base fabric (i), a well-known impregnated base fabric in which polyurethane resin is impregnated can also be used.

The aforementioned intermediate layer (ii) is composed of a moisture-curable hot-melt urethane resin containing an isocyanate group-containing hot-melt urethane prepolymer (A1) and a foaming agent composition (A2) Formed by things. With this foaming agent composition (A2), since the foamed structure can be easily formed in the intermediate layer (ii), an excellent texture can be obtained.

As the aforementioned foaming agent composition (A2), for example, N,N'-dinitrosopentamethylenetetramine, urea, azodimethamide, 4,4'-oxybis(benzenesulfon Hydrazine), sodium bicarbonate and other thermally decomposable blowing agents; boric acid. Among these, it is preferable to contain N,N'-dinitrosopentamethylenetetramine and urea from the viewpoint that a good foaming state can be formed and an excellent texture can be obtained.

As the amount of N,N'-dinitrosopentamethylenetetramine used, it is preferable from the viewpoint of forming a good foaming state and having less adverse effects on the mechanical properties of the intermediate layer (ii) It is the range of 3-50 mass% in the said foaming agent composition (A2), More preferably, it is the range of 5-40 mass %.

Since the aforementioned urea functions as a foaming aid for the aforementioned N,N'-dinitrosopentamethylenetetramine, it is preferably used in combination. As the amount of the aforementioned urea used, it can be formed well in the film. From the viewpoint of the foaming state of, it is preferably in the range of 3-50% by mass in the aforementioned foaming agent composition (A2), more preferably in the range of 8-40% by mass.

As the mass ratio of the aforementioned N,N'-dinitrosopentamethylenetetramine to urea [(N,N'-dinitrosopentamethylenetetramine)/(urea)], from the film From the viewpoint that a good foaming state can also be formed, it is preferably in the range of 10/90 to 90/10, and more preferably in the range of 30/70 to 70/30.

In addition, as the blowing agent composition (A2), in order to uniformly mix the blowing agent with the hot-melt urethane prepolymer (A1), it is preferable to further contain a polyol (p-a).

As the aforementioned polyol (pa), for example, polyester polyol, polyether polyol, polycarbonate polyol, polyacrylic polyol, polyolefin polyol, castor oil polyol, polyol, etc. can be used; Copolymer etc. These polyols can be appropriately determined in accordance with the use of the foamed hardened product, and can be used alone or in combination of two or more.

The number average molecular weight of the polyol (pa) is preferably in the range of 500 to 10,000, and more preferably 700 to, from the viewpoint of easy mixing in the hot melt urethane prepolymer (A1). The range of 5,000. In addition, the number average molecular weight of the aforementioned polyol (p-a) represents a value measured by a gel permeation chromatography (GPC) method.

As the usage amount of the aforementioned polyol (pa), it is preferable from the viewpoint of the ease of mixing with the aforementioned hot-melt urethane prepolymer (A1) and from the viewpoint of the mechanical properties of the foamed hardened product It is in the range of 30 to 90% by mass in the aforementioned foaming agent composition (A2), more preferably in the range of 40 to 80% by mass.

In addition, the foaming agent composition (A2) may further contain boric acid from the viewpoint of being able to form a further excellent foaming structure.

As the use amount in the case of using boric acid, it is preferably in the range of 5 to 150 parts by mass, and more preferably in the range of 10 to 120 parts by mass relative to 100 parts by mass of the aforementioned urea.

As the amount of the aforementioned foaming agent composition (A2) used, it never causes a decrease in the mechanical properties of the intermediate layer (ii), and a synthetic leather with a good texture can be obtained, and even a film can maintain a good foaming state From a viewpoint, the range of 1-30 mass parts is preferable with respect to 100 mass parts of the aforementioned hot-melt urethane prepolymer (A1), and the range of 5-25 mass parts is more preferable.

The aforementioned hot-melt urethane prepolymer (A1) having an isocyanate group is a solid at room temperature, preferably a melted one at a temperature of 80 to 120°C. The aforementioned hot-melt urethane prepolymer (A1) preferably has a melting viscosity at 100°C measured by a cone-plate viscometer in the range of 100 to 100,000 mPa･s, more preferably 500 to 70,000 mPa･s The scope of those. In addition, the melting viscosity of the aforementioned hot-melt urethane prepolymer (A1) means that the aforementioned hot-melt urethane prepolymer (A1) is melted at 100°C for 1 hour and then measured with a cone-plate viscometer. Value.

As the aforementioned hot-melt urethane prepolymer (A1), well-known ones can be used. For example, a reaction product of a polyol (a1) and a polyisocyanate (a2) can be used.

As the polyol (a1), the same as the polyol (p-a) can be used, and these polyols can be appropriately determined according to the application to be used, and can be used alone or in combination of two or more. Among these, when the synthetic leather of the present invention is used for applications requiring excellent bending resistance and hydrolysis resistance, it is preferable to use 50% by mass or more of polyoxytetraethylene in the polyol (a1). Polyoxy tetramethylene glycol is more preferably used in the range of 60 to 90% by mass. In addition, when the synthetic leather of the present invention is used for applications requiring excellent durability, it is preferable to use 50% by mass or more of polycarbonate polyol in the polyol (a1), and more preferably 60~ Use in the range of 90% by mass.

The number average molecular weight of the aforementioned polyol (a1) is preferably in the range of 500 to 7,000, more preferably in the range of 700 to 4,000 from the viewpoint of mechanical properties. In addition, the number average molecular weight of the aforementioned polyol (a1) represents a value measured by a gel permeation chromatography (GPC) method.

As the aforementioned polyisocyanate (a2), for example, polymethylene polyphenyl polyisocyanate, diphenylmethane diisocyanate, polydiphenylmethane diisocyanate, carbodiimide modified diphenylmethane diisocyanate, xylylene diisocyanate can be used. Diisocyanate, phenylene diisocyanate, phenylene diisocyanate, naphthalene diisocyanate and other aromatic polyisocyanates; hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate Aliphatic or alicyclic polyisocyanates such as isocyanate, dicyclohexylmethane diisocyanate, and tetramethylxylylene diisocyanate. These polyisocyanates can be used alone or in combination of two or more kinds. Among these, from the viewpoint of obtaining good reactivity and mechanical properties, aromatic polyisocyanate is preferably used, and diphenylmethane diisocyanate and/or xylylene diisocyanate are more preferably used.

As a method for producing the hot-melt urethane prepolymer (A1), for example, the polyol (a1) is dropped in a reaction vessel in which the polyisocyanate (a2) is placed, and then heated to It is produced by reacting the isocyanate group which the said polyisocyanate (a2) has in excess with respect to the hydroxyl group which the said polyol (a1) has.

As the equivalent ratio of the isocyanate group of the polyisocyanate (a2) to the hydroxyl group of the polyol (a1) when the hot-melt urethane prepolymer (A1) is produced ([NCO/OH] ), from the viewpoint of mechanical strength, it is preferably in the range of 1.1 to 5, more preferably in the range of 1.5 to 3.5.

The isocyanate group content of the hot-melt urethane prepolymer (A1) (hereinafter abbreviated as "NCO%") is preferably in the range of 1.1 to 5% by mass from the viewpoint of mechanical strength, and more Preferably, it is in the range of 1.5 to 4% by mass. In addition, the isocyanate group content rate of the said hot-melt urethane prepolymer (A1) shows the value measured by a potentiometric method based on JISK1603-1:2007.

The moisture-curable hot-melt urethane composition of the present invention contains the aforementioned hot-melt urethane prepolymer (A1) and the aforementioned blowing agent composition (B) as essential components, However, other additives may be contained as needed.

As the aforementioned other additives, for example, urethane catalysts, silane coupling agents, thixotropic agents, antioxidants, plasticizers, fillers, dyes, pigments, waxes, etc. can be used. These additives can be used alone or in combination of two or more.

The aforementioned skin layer (iii) must use an anionic urethane resin (X) having an anionic group concentration of 0.15 mmol/g or less and a urethane resin composition of water (Y). If the concentration of the anionic group is in this range, the introduction amount of the hydrophilic group is small, and therefore, even for chemicals having high polarity such as ethanol, excellent resistance and hydrolysis resistance can be obtained. The concentration of the anionic group of the urethane resin (X) is preferably 0.005 mmol/g or more, more preferably 0.01 mmol/g or more, from the viewpoint of obtaining more excellent chemical resistance. , Preferably 0.1 mmol/g or less, more preferably 0.07 mmol/g or less, preferably 0.005 to 0.1 mmol/g or less, more preferably 0.01 to 0.07 mmol/g. In addition, the concentration of the anionic group of the aforementioned urethane resin (X) means the number of moles of anionic groups derived from the raw materials used for the production of the aforementioned urethane resin having anionic groups. The value obtained by dividing by the total mass of each raw material constituting the urethane resin (X).

The introduction method of the anionic group in the said urethane resin (X) is the same as that of the said urethane resin (A). Among these, as the aforementioned urethane resin (X), it can be emulsified with a small amount of anionic groups, has excellent dispersibility to water (Y), and can obtain further excellent chemical resistance, and From the viewpoint of hydrolysis resistance, a urethane resin having a sulfonyl group using a compound having a sulfonyl group as a raw material is preferred.

As the aforementioned urethane resin (X), specifically, for example, the raw materials used to produce the aforementioned anionic group-containing urethane resin, polyisocyanate (x1), polyol (x2) can be used , Reactant with chain extender (x3).

As the usage amount of the raw material used to manufacture the aforementioned anionic group-containing urethane resin, from the viewpoint of obtaining further excellent chemical resistance and hydrolysis resistance, polyol (x2) is preferred Among them, 0.05% by mass or more, more preferably 0.1% by mass or more, still more preferably 0.3% by mass or more, particularly preferably 0.5% by mass or more, preferably 10% by mass or less, more preferably 7% by mass or less, and still more preferably It is 3% by mass or less, particularly preferably 2% by mass or less, preferably in the range of 0.05-10% by mass, more preferably in the range of 0.1-7% by mass, still more preferably in the range of 0.3-3% by mass, especially preferred It is in the range of 0.5-2% by mass.

As the aforementioned polyisocyanate (x1), for example, hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate can be used , Tetramethylxylylene diisocyanate, dimer acid diisocyanate, norbornene diisocyanate and other aliphatic or alicyclic polyisocyanates; phenylene diisocyanate, tolylene diisocyanate, diphenylmethane Aromatic polyisocyanates such as diisocyanate, naphthalene diisocyanate, polymethylene polyphenyl polyisocyanate, carbodiimide diphenylmethane polyisocyanate, etc. These polyisocyanates can be used alone or in combination of two or more kinds. Among these, from the viewpoint of obtaining further excellent chemical resistance and hydrolysis resistance, it is preferable to use aliphatic and/or alicyclic polyisocyanate, and more preferably to use isophorone diisocyanate. One or more polyisocyanates selected from the group consisting of, dicyclohexylmethane diisocyanate, and hexamethylene diisocyanate.

As the aforementioned polyol (x2), for example, polyether polyol, polyester polyol, polycarbonate polyol, dimer diol, acrylic polyol, polybutadiene polyol, etc. can be used. These polyols can be used alone or in combination of two or more kinds. Among these, from the viewpoint of obtaining further excellent chemical resistance and hydrolysis resistance, it is preferable to use polycarbonate polyol and/or polyester polyol, and the amount of polyol used is more suitable. It is preferably 20% by mass or more in the aforementioned polyol (x2), more preferably 30% by mass or more.

As the aforementioned polycarbonate polyol, it is preferable to use polycarbonate using hexanediol and/or ε-caprolactone as a raw material from the viewpoint of obtaining further excellent chemical resistance and hydrolysis resistance. Polyol.

As the aforementioned polyester polyol, from the viewpoint of obtaining further excellent chemical resistance and hydrolysis resistance, it is preferable to use a polyester polyol from butanediol, hexanediol, trimethylolpropane, and neopentyl One or more compounds selected from the group consisting of diols are used as raw material polyester polyols.

As the number average molecular weight of the aforementioned polyol (x2), from the viewpoint of further excellent chemical resistance, hydrolysis resistance, and mechanical strength, it is preferably in the range of 500 to 100,000, more preferably 800 to 10,000 The scope. In addition, the number average molecular weight of the aforementioned polyol (x2) represents a value measured by a gel permeation chromatography (GPC) method.

As the aforementioned chain extender (x3), for example, a chain extender having a hydroxyl group having a molecular weight of 50 or more and less than 500, a chain extender having an amine group, and the like can be used. These can be used alone or in combination of two or more.

As the aforementioned chain extender having a hydroxyl group, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol can be used , Hexamethylene glycol, sucrose, methylene glycol, glycerol, sorbitol and other aliphatic polyol compounds; bisphenol A, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl Aromatic polyol compounds such as base ether, 4,4'-dihydroxydiphenyl sulfide, hydrogenated bisphenol A, hydroquinone; water, etc. These chain extenders can be used alone or in combination of two or more kinds.

、2-甲基哌

、2,5-二甲基哌

、異佛酮二胺、4,4’-二環己基甲烷二胺、3,3’-二甲基-4,4’-二環己基甲烷二胺、1,2-環己二胺、1,4-環己二胺、胺乙基乙醇胺、聯胺、二伸乙三胺、三伸乙四胺、己二醯肼等。此等鏈伸長劑能單獨使用也能將2種以上合併使用。As the aforementioned chain extender having an amine group, for example, ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperidine

, 2-methylpiperidine

, 2,5-Dimethylpiperidine

, Isophorone diamine, 4,4'-dicyclohexylmethanediamine, 3,3'-dimethyl-4,4'-dicyclohexylmethanediamine, 1,2-cyclohexanediamine, 1 , 4-cyclohexanediamine, amine ethylethanolamine, hydrazine, ethylene triamine, ethylene tetramine, hexamethylene hydrazine, etc. These chain extenders can be used alone or in combination of two or more kinds.

As the aforementioned chain extender (x3), from the viewpoint of obtaining further excellent chemical resistance, hydrolysis resistance, and light resistance, it is preferable to use a chain extender having an amine group, and it is preferable to use a More than one chain extender selected from the group consisting of isophorone diamine, hydrazine, and hexamethylene hydrazine. The use amount of these preferred chain extenders is preferably 30% by mass or more in the chain extender (x3), more preferably 40% by mass or more, and still more preferably 50% by mass or more.

As the use amount of the aforementioned chain extender (x3), from the viewpoint of further improving the durability, chemical resistance, hydrolysis resistance, and light resistance of the film, it is preferable to constitute the urethane resin (X The total mass of the raw materials of) is in the range of 0.5-20% by mass, more preferably in the range of 1-10% by mass.

As a method of producing the aforementioned urethane resin (X), for example, the following method can be mentioned: the aforementioned polyisocyanate (x1) and polyol (x2) are reacted to obtain a urethane precursor having an isocyanate group For the polymer, the chain extender (x3) and the raw materials used for producing the urethane resin having an anionic group are reacted, and then water (Y) is added. These reactions are preferably carried out at a temperature of, for example, 50 to 100°C for 3 to 10 hours.

In addition, when a chain extender having a hydroxyl group and a chain extender having an amine group are used in combination as the chain extender (x3), the following method is preferred: the polyisocyanate (x1) and the polyol ( x2) and a chain extender having a hydroxyl group are reacted to obtain a urethane prepolymer having an isocyanate group, and then a chain extender having an amine group is used and in order to produce the aforementioned urethane prepolymer having an anionic group The raw materials used in the acid ester resin are reacted, and then water (Y) is added. These reactions are preferably carried out at a temperature of, for example, 50 to 100°C for 3 to 10 hours.

As the raw material used to manufacture the urethane resin having a hydrophilic group, the polyol (x2), and the sum of the hydroxyl groups and amino groups of the chain extender (x3) are combined with the polyisocyanate ( x1) The molar ratio [(isocyanate group)/(hydroxyl and amino group)] of the isocyanate group possessed is preferably in the range of 0.8 to 1.2, more preferably in the range of 0.9 to 1.1.

As the aforementioned molar ratio [(isocyanate group)/(hydroxyl and amino group)] when obtaining the aforementioned isocyanate group-containing urethane prepolymer, it is preferably in the range of 1.1 to 3.5, more preferably 1.3 to The range of 2.5. In addition, in the subsequent chain extension step, the equivalent ratio of the isocyanate group reactive group of the chain extender to the free isocyanate group of the aforementioned urethane prepolymer can be preferably in the range of 40 to 100%. More preferably, the reaction proceeds in the range of 70 to 100%.

As the weight average molecular weight of the aforementioned urethane resin (X), from the viewpoint of further improving the durability, chemical resistance, hydrolysis resistance, and light resistance of the film, it is preferably 50,000 or more, more preferably It is 70,000 or more, preferably 250,000 or less, more preferably 200,000 or less, preferably in the range of 50,000 to 250,000, more preferably in the range of 70,000 to 200,000. In addition, the weight average molecular weight of the aforementioned urethane resin (X) represents a value measured by a gel permeation chromatography (GPC) method.

烷等的醚化合物；乙酸乙酯、乙酸丁酯等的乙酸酯化合物；乙腈等的腈化合物；二甲基甲醯胺、N-甲基吡咯啶酮等的醯胺化合物等。此等有機溶媒能單獨使用也能將2種以上合併使用。作為前述有機溶劑，較佳為使用丙酮及/或甲基乙基酮，更佳為丙酮。此外，前述有機溶劑較佳為在得到胺基甲酸酯樹脂組成物時藉由蒸餾法等去除。In addition, an organic solvent can also be used when manufacturing the aforementioned urethane resin (X). As the aforementioned organic solvent, for example, ketone compounds such as acetone and methyl ethyl ketone; tetrahydrofuran, two

Ether compounds such as alkane; acetate compounds such as ethyl acetate and butyl acetate; nitrile compounds such as acetonitrile; amide compounds such as dimethylformamide and N-methylpyrrolidone. These organic solvents can be used alone or in combination of two or more. As the aforementioned organic solvent, acetone and/or methyl ethyl ketone is preferably used, and acetone is more preferred. In addition, the aforementioned organic solvent is preferably removed by distillation or the like when the urethane resin composition is obtained.

As the water (Y), the same as the water (B) can be used. The content of the aforementioned water (Y) is preferably in the range of 30 to 80% by mass in the urethane resin composition from the viewpoints of workability, coating properties, and storage stability, and more preferably 35 to Range of 70% by mass.

As the aforementioned urethane resin composition, in addition to the aforementioned urethane resin (X) and the aforementioned water (Y), other additives may be contained as necessary.

As the aforementioned other additives, for example, emulsifiers, coagulants, urethane catalysts, silane coupling agents, fillers, thixotropic agents, adhesive agents, waxes, heat stabilizers, light stabilizers, Fluorescent brightener, foaming agent, pigment, dye, conductivity imparting agent, antistatic agent, moisture permeability enhancer, water repellent, oil repellent, hollow foam, flame retardant, water absorbent, absorbent Wetting agent, deodorant, foam stabilizer, anti-caking agent, anti-hydrolysis agent, tackifier, etc. These additives can be used alone or in combination of two or more.

Next, the manufacturing method of the synthetic leather of this invention is demonstrated.

As a manufacturing method of the aforementioned synthetic leather, for example, the following method can be mentioned: the urethane resin composition for forming the skin layer is coated on the base material after the release treatment, and the skin layer is obtained by drying. (iii), next, After the hot-melt urethane prepolymer (A1) is heated and melted, the foaming agent composition (A2) is mixed, and the mixture is coated on the skin layer (iii), and then, by using the hot-melt The urethane prepolymer (A1) is heated to a temperature higher than the melting temperature to form the intermediate layer (ii), and then the base fabric (i) is bonded to the intermediate layer (ii).

As a method of coating the urethane resin composition for forming the skin layer, for example, the use of a coater, a roll coater, a sprayer, a T-die coater, a knife coater, and a cutaway wheel coater (comma coater) and other methods.

As a drying method of the said urethane resin composition, the method of performing 1-10 minutes at 40-130 degreeC is mentioned, for example. The thickness of the obtained skin layer (iii) is appropriately determined in accordance with the application for which the synthetic leather is used, but is in the range of, for example, 0.5 to 100 μm.

As a method of mixing the aforementioned foaming agent composition (A2) with the hot-melt urethane prepolymer (A1) melted by heating, for example, the use of a batch mixer, a static mixer, and a rotor / Mixing devices such as stators, two-liquid mixing devices, etc.

As a method of coating the aforementioned moisture-curable hot-melt urethane composition on the skin layer (iii) formed on the release paper, for example, use of a coater, roll coater, sprayer, T Type coater, knife coater, missing angle wheel coater and other methods.

In addition, the coating of the moisture-curable hot-melt urethane composition foams and increases its thickness by post-heating described later. Therefore, it is preferable to consider the degree of foaming described later, etc. To determine the thickness of the aforementioned coating.

Next, heat treatment is performed at a temperature higher than the heating melting temperature of the hot-melt urethane prepolymer (A1) to promote the blowing agent composition (A2) (especially (A2-1) ) Foaming and hardening to make the intermediate layer (ii). As the aforementioned heat treatment at this time, for example, it is in the range of 100 to 150°C. From the viewpoint of easily suppressing adverse effects on the base material and deterioration of the physical properties of the synthetic leather due to thermal history, it is more preferably 110 to 140°C range. As the time of the aforementioned heat treatment, for example, 1 to 10 minutes is preferable.

After forming the aforementioned intermediate layer (ii), a synthetic leather can be obtained by bonding the base fabric (i) to the aforementioned intermediate layer (ii), but before and/or after bonding the aforementioned base fabric (i), For the purpose of curing the intermediate layer (ii), it may be post-cured at a temperature of 20 to 80°C for 1 to 7 days.

The thickness of the intermediate layer (ii) of the synthetic leather obtained by the above method is, for example, in the range of 10 to 500 μm, and a good foaming state can be formed within this range. The aforementioned thickness can be appropriately determined according to the application for which the synthetic leather of the present invention is used. Furthermore, in the present invention, a good foaming state can be maintained even in a film. As its thickness, for example, it is less than 100 μm, preferably in the range of 20 to 90 μm, more preferably in the range of 30 to 80 μm, and particularly preferably 50 ~70μm range.

The foam remaining in the intermediate layer (ii) is mainly foamed by the post-heating of (A2-1), but the foaming degree of the intermediate layer (ii) is preferably 1.2 or more, It is more preferably in the range of 1.5 to 3, and still more preferably in the range of 1.7 to 2.8. In addition, the foaming degree of the aforementioned intermediate layer (ii) represents the difference between the volume (V ₁ ) before foaming and the volume (V ₂ ) after foaming of the aforementioned moisture-curing hot-melt urethane composition Ratio (V ₂ /V ₁ ) calculated value.

After the aforementioned synthetic leather is manufactured, it may be aged at 30 to 100°C for 1 to 10 days, if necessary.

In the aforementioned synthetic leather, a porous layer, a surface treatment layer, etc. can also be used as necessary. As a material for forming these layers, well-known ones can be used.

In summary, the synthetic leather of the present invention uses a solvent-free moisture-curing hot-melt urethane resin composition to form the middle layer and a water-based urethane resin composition to form the skin layer. , So it is excellent in environmental response, and excellent in abrasion resistance, hydrolysis resistance, and texture. [Example]

[Synthesis Example 1] >Preparation of moisture-curing hot-melt urethane resin composition (RHM-1 for intermediate layer)> In a reaction vessel equipped with a thermometer, a stirrer, an inert gas inlet, and a reflux condenser, 70 parts by mass of polyoxytetramethylene glycol (number average molecular weight: 2,000, hereinafter abbreviated as "PTMG") is charged. , 30 parts by mass of polyester polyol (reaction product of 1,6-hexanediol and adipic acid, number average molecular weight: 2,000, abbreviated as "PEs(1)" below), dehydrated under reduced pressure to Until the moisture content becomes 0.05% by mass or less. Next, 25 parts by mass of 4,4'-diphenylmethane diisocyanate (MDI) was added, the temperature was raised to 100°C, and the reaction was carried out for about 3 hours until the isocyanate group content reached a certain level to obtain NCO%: 3.3 with isocyanate -Based hot-melt urethane prepolymer. In addition, 5 parts by mass of polyoxypropylene triol ("MN-3050" manufactured by Mitsui Chemicals Co., Ltd., number average molecular weight: 3,000) and 2.5 parts by mass of N,N'-dinitrosopenta Methylenetetramine and 2.5 parts by mass of urea are mixed to prepare a foaming agent composition. Use RHM-1 as an intermediate layer.

[Synthesis Example 2] >Preparation of moisture-curing hot-melt urethane resin composition (RHM-2 for intermediate layer)> In a reaction vessel equipped with a thermometer, a stirrer, an inert gas inlet, and a reflux condenser, 70 parts by mass of polycarbonate polyol ("Nipporan 980R" manufactured by Japan Polyurethane Industry Co., Ltd., Number average molecular weight: 2,600, hereinafter abbreviated as "PC".), 30 parts by mass of PEs (1), dehydrated under reduced pressure until the moisture content becomes 0.05% by mass or less. Next, 25 parts by mass of 4,4'-diphenylmethane diisocyanate was added, the temperature was raised to 100°C, and the reaction was carried out for about 3 hours until the isocyanate group content became constant, to obtain a hot melt with isocyanate groups with NCO%: 3.2 Urethane prepolymer. In addition, 5 parts by mass of polyoxypropylene triol ("MN-3050" manufactured by Mitsui Chemicals Co., Ltd., number average molecular weight: 3,000) and 2.5 parts by mass of N,N'-dinitrosopenta Methylenetetramine and 2.5 parts by mass of urea are mixed to prepare a foaming agent composition. Use RHM-2 as an intermediate layer.

[Synthesis Example 3] >Preparation of moisture-curing hot-melt urethane resin composition (RHM-3 for intermediate layer)> It carried out similarly to Synthesis Example 1, and obtained the hot-melt urethane prepolymer which has an isocyanate group. In addition, 5 parts by mass of polyoxypropylene triol ("MN-3050" manufactured by Mitsui Chemicals Co., Ltd., number average molecular weight: 3,000) and 3.5 parts by mass of N,N'-dinitrosopenta Methylenetetramine and 1.5 parts by mass of urea were mixed to prepare a foaming agent composition. Use RHM-3 as an intermediate layer.

[Synthesis Example 4] >Preparation of moisture-curing hot-melt urethane resin composition (RHM-4 for intermediate layer)> It carried out similarly to Synthesis Example 1, and obtained the hot-melt urethane prepolymer which has an isocyanate group. In addition, 5 parts by mass of polyoxypropylene triol ("MN-3050" manufactured by Mitsui Chemicals Co., Ltd., number average molecular weight: 3,000) and 2.5 parts by mass of N,N'-dinitrosopenta Methylenetetramine, 2.5 parts by mass of urea, and 0.5 parts by mass of boric acid are mixed to prepare a foaming agent composition. Use RHM-4 as an intermediate layer.

[Synthesis example 4] Preparation of urethane resin (X-1) composition for skin layer formation In a four-necked flask equipped with a stirrer, a reflux cooling tube, a thermometer, and a nitrogen introduction tube, 120 parts by mass of polycarbonate polyol (ETERNACOLL manufactured by Ube Industries Co., Ltd.) was heated at 70°C under nitrogen flow. UH-200, number average molecular weight: 2,000"), 280 parts by mass of polytetramethylene glycol (number average molecular weight: 2,000) are uniformly mixed, 100 parts by mass of isophorone diisocyanate are added, and the reaction is carried out at 100°C In 6 hours, a urethane prepolymer having isocyanate was obtained. Next, this urethane prepolymer was cooled to 60 degreeC, 928 mass parts of acetones were added, and it melt|dissolved uniformly. Add 191 parts by mass of ion exchange water, 30 parts by mass of isophorone diamine, and 6 parts by mass of N-2-aminoethane-2-aminosulfon to this urethane prepolymer solution. Mixture of sodium. Next, 155 parts by mass of ion exchange water was added. After the reaction, the acetone was distilled under reduced pressure to obtain a urethane resin (X-1) composition (non-volatile component: 60% by mass, anionic group concentration: 0.059 mmol/g).

[Synthesis Example 5] Preparation of urethane resin (X-2) composition for skin layer formation In a four-necked flask equipped with a stirrer, a reflux cooling tube, a thermometer, and a nitrogen introduction tube, 120 parts by mass of polycarbonate polyol (ETERNACOLL manufactured by Ube Industries Co., Ltd.) was heated at 70°C under nitrogen flow. UH-200, number average molecular weight: 2,000"), 280 parts by mass of polytetramethylene glycol (number average molecular weight: 2,000), 12 parts by mass of "UNILUBE 50MB-72" manufactured by NOF Corporation (number average Molecular weight: 3,000) After uniformly mixing, 101 parts by mass of isophorone diisocyanate was added, and the reaction was carried out at 100°C for 6 hours to obtain a urethane prepolymer having an isocyanate. Next, this urethane prepolymer was cooled to 60 degreeC, 953 mass parts of acetones were added, and it melt|dissolved uniformly. Add 193 parts by mass of ion exchange water, 30 parts by mass of isophorone diamine, and 4 parts by mass of N-2-aminoethane-2-aminosulfon to this urethane prepolymer solution. Mixture of sodium. Next, 172 parts by mass of ion exchange water was added. After completion of the reaction, acetone was distilled under reduced pressure to obtain a urethane resin (X-2) composition (non-volatile content: 60% by mass, anionic group concentration: 0.039 mmol/g).

[Synthesis example 6] Preparation of urethane resin (X-3) composition for skin layer formation In a four-necked flask equipped with a stirrer, a reflux cooling tube, a thermometer, and a nitrogen introduction tube, 280 parts by mass of polycarbonate polyol (ETERNACOLL manufactured by Ube Industries Co., Ltd.) was heated at 70°C under nitrogen flow. UH-200, number average molecular weight: 2,000"), 120 parts by mass of polytetramethylene glycol (number average molecular weight: 2,000) are uniformly mixed, 50 parts by mass of isophorone diisocyanate, and 38 parts by mass of hexamethylene glycol are added. The methylene diisocyanate was reacted at 100°C for 6 hours to obtain a urethane prepolymer having an isocyanate. Next, this urethane prepolymer was cooled to 60 degreeC, 906 mass parts of acetones were added, and it melt|dissolved uniformly. Add 90 parts by mass of ion exchange water, 11 parts by mass of 80% by mass hydrazine hydrate, and 5 parts by mass of N-2-aminoethane-2-aminosulfon to this urethane prepolymer solution. Mixture of sodium. Next, 246 parts by mass of ion exchange water was added. After completion of the reaction, acetone was distilled under reduced pressure to obtain a urethane resin (X-3) composition (non-volatile component: 60% by mass, anionic group concentration: 0.053 mmol/g).

[Comparative Synthesis Example 1] >Preparation of water-based urethane resin composition (RHM’-1 for intermediate layer)> Except not preparing the foaming agent composition, the same procedure as in Synthesis Example 1 was carried out to obtain RHM'-1 for the intermediate layer.

[Comparative Synthesis Example 2] Preparation of urethane resin (XR-1) composition for skin layer formation In a four-necked flask equipped with a stirrer, reflux cooling tube, thermometer, and nitrogen introduction tube, 100 parts by mass of polycarbonate polyol (ETERNACOLL manufactured by Ube Industries Co., Ltd. UH-200, number average molecular weight: 2,000"), 186 parts by mass of polytetramethylene glycol (number average molecular weight: 2,000), 24 parts by mass of 2,2-dimethylolpropionic acid are uniformly mixed, and then added 143 parts by mass of isophorone diisocyanate was reacted at 100°C for 6 hours to obtain a urethane prepolymer having isocyanate. Next, this urethane prepolymer was cooled to 60 degreeC, 910 mass parts of acetones were added, and it melt|dissolved uniformly. After adding 18 parts by mass of triethylamine to this urethane prepolymer solution and neutralizing the carboxyl groups, 922 parts by mass of ion exchange water was added, and 44 parts by mass of isophorone diamine were added to react. After completion of the reaction, acetone was distilled under reduced pressure to obtain a urethane resin (XR-1) composition (non-volatile component: 35% by mass, anionic group concentration: 0.36 mmol/g).

[Example 1] By including 100 parts by mass of the skin layer forming urethane resin (X-1) composition, 10 parts by mass of water-dispersible black pigment ("Dilak HS-9530" manufactured by DIC Co., Ltd.), 1 part by mass of an associative tackifier ("Hydran Assistor T10" manufactured by DIC Co., Ltd.) is applied to a flat release paper (Ajinomoto Co., Ltd.) so that the film thickness after drying becomes 30μm. ("DN-TP-155T"), dried at 70°C for 2 minutes, and further dried at 120°C for 2 minutes to obtain a skin layer. Next, 100 parts by mass of the hot-melt urethane prepolymer obtained in Synthesis Example 1 was heated to 100°C and melted. To this, 10 parts by mass of the blowing agent composition obtained in Synthesis Example 1 was added and mixed, and the resulting moisture-curing hot-melt urethane was treated with a cut-off wheel coater to have a thickness of 30 μm. The composition was coated on the aforementioned skin layer, heated at 120°C for 5 minutes, and then laminated to the non-woven fabric, and then left for 3 days under the conditions of a temperature of 23°C and a relative humidity of 65% to obtain an intermediate layer (ii) with a thickness of 45μm The synthetic leather.

[Examples 2 to 8, Comparative Examples 1 to 2] Except having changed the used RHM for the intermediate layer, PUD for the skin layer, and processing conditions as shown in Tables 1 to 2, it carried out similarly to Example 1, and obtained synthetic leather.

[Measurement method of number average molecular weight] The number average molecular weight of polyols and the like used in the synthesis examples is measured by gel permeation chromatography (GPC) under the following conditions.

Measuring device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Co., Ltd.) Column: The following columns manufactured by Tosoh Co., Ltd. were connected in series and used. "TSKgel G5000" (7.8mmI.D.×30cm)×1 "TSKgel G4000" (7.8mmI.D.×30cm)×1 "TSKgel G3000" (7.8mmI.D.×30cm)×1 "TSKgel G2000" (7.8mmI.D.×30cm)×1 Detector: RI (differential refractometer) Column temperature: 40℃ Eluent: Tetrahydrofuran (THF) Flow rate: 1.0mL/min Injection volume: 100μL (tetrahydrofuran solution with a sample concentration of 0.4% by mass) Standard sample: Use the following standard polystyrene to make a calibration line.

(Standard polystyrene) "TSKgel Standard Polystyrene A-500" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene A-1000" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene A-2500" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene A-5000" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-1" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-2" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-4" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-10" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-20" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-40" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-80" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-128" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-288" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-550" manufactured by Tosoh Co., Ltd.

[Measuring method of melting viscosity] The hot-melt urethane prepolymers obtained in the synthesis example were melted at 100°C for 1 hour, and then 1 ml was sampled, and the cone-plate viscometer (M･S･T Engineering Co., Ltd. digital cone viscometer "CV -1S RT type", 40P cone, rotor rotation number: 50rpm) to measure the melt viscosity at 100°C.

[Method for measuring the degree of foaming of the intermediate layer (ii)] In the examples and comparative examples, the measurement is made after adding molten hot-melt urethane prepolymer (A1) and foaming agent composition (A2) The foaming degree is calculated from the ratio (V ₂ /V ₁ ) of the volume (V ₁ ) of the foamed intermediate layer and the volume of the foamed intermediate layer (V ₂ ).

[Evaluation method of foaming state] The intermediate layer of the synthetic leather obtained in the Examples and Comparative Examples was observed using a scanning electron microscope "SU3500" (200 times magnification) manufactured by Hitachi High Technologies Co., Ltd. and evaluated as follows. "T": A good foaming state can be confirmed. "F": A good foaming state cannot be confirmed.

[Method of evaluating texture] The texture of the foamed cured product and the cured product obtained in the examples and comparative examples was evaluated from the touch. "A": Very flexible, no irregularities can be confirmed. "B": It has good flexibility, and no irregularities are confirmed. "C": Hard, or irregularities are confirmed.

[Evaluation of Chemical Resistance] 10 drops of ethanol were dropped on the skin layer of the synthetic leather obtained in the Examples and Comparative Examples, the appearance after being left for 24 hours was observed, and the evaluation was performed as follows. "A": There is no abnormal appearance. "B": The appearance is slightly whitened. "C": The appearance has a large yellowing.

[Evaluation method of hydrolysis resistance] The synthetic leathers obtained in the examples and comparative examples were left for 5 weeks under the conditions of 70°C and 95% humidity. Based on subsequent appearance observation and finger touch, the evaluation was performed as follows. "A": Appearance‧No abnormalities in finger touch. "B": The appearance has changed gloss, but no abnormality is confirmed by finger touch. "C": The appearance changes in gloss and stickiness is confirmed.

[Table 1] Table 1 Example 1 Example 2 Example 3 Example 4 Example 5 Intermediate layer (II) Moisture hardening type hot-melt urethane resin composition RHM-1 for middle layer RHM-2 for middle layer RHM-3 for middle layer RHM-4 for middle layer RHM-1 for middle layer Hot melt urethane prepolymer (A1) Polyol (a1) PTMG PC PTMG PTMG PTMG PEs(1) PEs(1) PEs(1) PEs(1) PEs(1) Polyisocyanate (a2) MDI MDI MDI MDI MDI NCO% of hot melt urethane prepolymer (A1) 3.3 3.2 3.3 3.3 3.3 Melting (A1) temperature (℃) 100 100 100 100 100 Melting viscosity at 100℃ (mPa･s) 2000 2500 2000 2000 2000 Foaming agent composition (A2) (The following parts by mass are relative to 100 parts by mass of (A1)) N,N'-Dinitrosopentamethylenetetramine (parts by mass) 2.5 2.5 3.5 2.5 2.5 Urea (parts by mass) 2.5 2.5 1.5 2.5 2.5 Polyol (pa) (parts by mass) MN3050 (parts by mass) 5 5 5 5 5 Boric acid (parts by mass) 0.5 (N,N'-Dinitrosopentamethylenetetramine)/(urea) mass ratio 50/50 50/50 70/30 50/50 50/50 After heating temperature (℃) 120 120 120 120 120 Thickness when the mixture is applied (μm) 30 30 30 30 30 Thickness of the middle layer (ii) (μm) 45 45 45 50 45 Foaming degree of the middle layer 1.8 1.8 2.2 2.1 1.8 Epidermis (III) Urethane resin composition X-1 for epidermis X-2 for epidermis X-3 for epidermis X-1 for epidermis X-2 for epidermis Concentration of anionic group of urethane resin (X) (mmol/g) 0.059 0.039 0.053 0.059 0.039 Foaming state of the intermediate layer (ii) T T T T T Texture evaluation A A A A A Evaluation of chemical resistance A A A A A Evaluation of hydrolysis resistance A A A A A

[Table 2] Table 2 Example 6 Example 7 Example 8 Comparative example 1 Comparative example 2 Intermediate layer (II) Moisture hardening type hot-melt urethane resin composition RHM-3 for middle layer RHM-1 for middle layer RHM-2 for middle layer RHM'-1 for middle layer RHM-1 for middle layer Hot melt urethane prepolymer (A1) Polyol (a1) PTMG PTMG PC PTMG PTMG PEs(1) PEs(1) PEs(1) PEs(1) PEs(1) Polyisocyanate (a2) MDI MDI MDI MDI MDI NCO% of hot melt urethane prepolymer (A1) 3.3 3.3 3.2 3.3 3.3 Melting (A1) temperature (℃) 100 100 100 100 100 Melting viscosity at 100℃ (mPa･s) 2000 2000 2500 2000 2000 Foaming agent composition (A2) (The following parts by mass are relative to 100 parts by mass of (A1)) N,N'-Dinitrosopentamethylenetetramine (parts by mass) 3.5 2.5 2.5 2.5 Urea (parts by mass) 1.5 2.5 2.5 2.5 Polyol (pa) (Quality Department) MN3050 (Quality Department) 5 5 5 5 Boric acid (parts by mass) (N,N'-Dinitrosopentamethylenetetramine)/(urea) mass ratio 70/30 50/50 50/50 50/50 After heating temperature (℃) 120 120 120 no Thickness when the mixture is applied (μm) 30 30 30 30 Thickness of the middle layer (ii) (μm) 45 45 45 30 Foaming degree of the middle layer 2.2 1.8 1.8 - Epidermis (III) Urethane resin composition X-1 for epidermis X-2 for epidermis X-3 for epidermis X-1 for epidermis XR-1 for epidermis Concentration of anionic group of urethane resin (X) (mmol/g) 0.059 0.039 0.053 0.059 0.36 Foaming state of the intermediate layer (ii) T T T F T Texture evaluation A A A C A Evaluation of chemical resistance A A A A C Evaluation of hydrolysis resistance A A A A C

Examples 1 to 8 of the synthetic leather of the present invention show that it is excellent in hydrolysis resistance, chemical resistance, and texture.

On the other hand, Comparative Example 1 used a moisture-curable hot-melt urethane resin composition that did not use a foaming agent composition to form an intermediate layer, and the texture was obviously poor.

In Comparative Example 2, the surface skin layer uses an anionic urethane resin with a higher concentration of anionic groups than specified in the present invention, and has poor hydrolysis resistance and chemical resistance.

no.

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Claims (3)

A synthetic leather, which is a synthetic leather having at least a base cloth (i), an intermediate layer (ii), and a skin layer (iii), and is characterized by: The intermediate layer (ii) is formed of a moisture-curable hot-melt urethane resin composition, and the moisture-curable hot-melt urethane resin composition contains: a hot-melt amine having an isocyanate group Carbamate prepolymer (A1), and foaming agent composition (A2), The skin layer (iii) is formed of a urethane resin composition containing: anionic urethane having an anionic group concentration of 0.15 mmol/g or less Resin (X), and water (Y). Such as the synthetic leather of claim 1, wherein the foaming agent composition (A2) contains N,N'-dinitrosopentamethylenetetramine and urea. The synthetic leather of claim 1 or 2, wherein the anionic group of the anionic urethane resin (X) is a sulfonyl group.