JP3059259B2 - Leather-like sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leather-like sheet having a good texture. More specifically, the texture is achieved by using a polyurethane resin having excellent physical properties such as light resistance and mechanical properties obtained by blending and reacting specific components constituting the polyurethane resin in a specific composition in a specific order. The present invention provides a leather-like sheet having a good quality.

[0002]

2. Description of the Related Art Leather-like sheet materials having polyurethane as a skin layer are widely used as materials for seats for shoes, clothing, furniture, and vehicles such as automobiles. Demands for quality such as heat resistance and heat resistance are becoming more and more advanced. Many attempts have been made to satisfy these required performances by improving the properties of polyurethane resins. As one of the means, for example, the type of polyurethane and the composition of its components are changed.

Japanese Patent Publication No. 55-23956 proposes a synthetic leather using a special polycarbonate-based polyurethane urea elastomer and having excellent light resistance and hydrolysis resistance. JP-A-62-2817 discloses that a polyurethane using a polymer diol containing a 2-methyl-1,5-octanediol unit has excellent hydrolysis resistance, and a polyester-based polyurethane containing the unit. It is disclosed that a synthetic leather can be obtained by applying a solution to a substrate such as a fiber as a coating agent or an impregnating agent.
JP-A-58-144185 discloses that a polycarbonate-based polyurethane adhesive, an intermediate layer of a polyester-based polyurethane composed of a glycol carboxylic acid having 4 or more carbon atoms, and a polycarbonate polyurethane skin layer are sequentially laminated on a microporous composite fiber substrate. A flexible synthetic leather for vehicles is disclosed.

JP-A-2-33384 discloses a polyurethane obtained by reacting a polymer diol with an organic diisocyanate and a chain extender, wherein the polymer diol has the formula

Embedded image A synthetic leather using a polyurethane containing a structural unit represented by the following formula as a skin layer is disclosed. However, we cannot meet increasingly diversified and sophisticated social demands,
Further improvements are desired.

[0005] As another means, attempts have been made to improve the polymerization process of polyurethane. In producing a polyurethane resin, a so-called one-shot method in which necessary materials are simultaneously added is often used. However, in the polyurethane resin obtained by the method, the respective components used in the production are likely to be arranged in a statistical distribution according to the reactivity ratio and the charged composition ratio, or in the case of good flexibility, the cold resistance If the heat resistance is poor, the durability is good, the flexibility is poor, the cold resistance is poor, or the wet solidification is good, the light resistance is poor, and the above application properties are not sufficiently satisfied. Frequently occur, and many proposals for improvement have been made.

An isocyanate-terminated intermediate diisocyanate obtained by allowing a stoichiometric excess of an organic diisocyanate to act on a polymer diol, or a mixture of a polymer diol and a low molecular chain extender, is added to a low molecular chain extender, There have been proposed many so-called prepolymer methods in which a polyurethane resin is obtained by the action of a polymer. The arrangement of each component is controlled by the prepolymer method,
Although a certain improvement effect has been seen in improving the application characteristics,
The resulting isocyanate-terminated intermediate diisocyanate is highly reactive, often causing side reactions,
Often, the initial goal cannot be achieved. In addition, if a diisocyanate of a type that is significantly different in reactivity from the diisocyanate used for the production of intermediate resistance is added in the next step, it is difficult to obtain a smooth reaction. For some reason or other reasons, the above application characteristics are often not fully satisfied, and further improvement is desired.

Japanese Patent Publication No. 38-14048 discloses that instead of hexanediol polyester, each component is obtained by adding a diisocyanate to a polyester obtained from a glycol having at least 5 carbon atoms and a dicarboxylic acid.
０．７0.7 mol, produced with a molecular weight of about 900
Urethane elastomers obtained by methods using diester urethanes in the range of ~ 1200 have been shown to be very hard and have insufficient hydrolysis resistance and insufficient elasticity of the product. In other words, synthetic leathers and artificial leathers having a good hand cannot be obtained from the polyurethane resin obtained by the method disclosed in this publication.

JP-A-2-140217 discloses that in producing polyurethane from a polyisocyanate component and a polyol component, (A) a compound having an isocyanate group at an end obtained from an organic polyisocyanate and a derivative thereof; A polyol having a molecular weight of 500 to 1,000 containing two or more active hydrogen groups in the molecule, (C)
Polyol containing urethane bond, (D) molecular weight 50
0. A process for producing a polyurethane, characterized by reacting with a chain extender of 0 or less, (E) a polyvalent amine having a molecular weight of 100 to 5,000, and (F) a catalyst, a foaming agent and other additives as required. Is disclosed.

The publication preferably discloses a polyisocyanate, a polyether diol, a polyether triol, a mixture thereof, and a small amount of a polyether polyol having a valency of 4 or more as a component (C) of from 500 to 20.
And a polyol having a urethane bond obtained at an equivalent ratio of NCO group / active hydrogen group of 0.4 to 0.6 and a reaction temperature of 60 to 85 ° C. with respect to 100 parts by weight of the component (B). It has been shown that by using 200 parts by weight, flexibility and abrasion resistance are improved, and particularly when used for shoe soles, excellent performance is exhibited. Although it is described that it is also useful for synthetic leather, automobile parts, furniture, etc., it is shown that it is not useful when a polyester polyol is used as a polyol, and the polyurethane resin obtained by the method of the publication discloses that it is not useful. The polyurethanes used in the present invention can be obtained or not.

Japanese Patent Application Laid-Open No. 54-127500 discloses a non-yellowing type isocyanate as a polyisocyanate component of a urethane polymer, and about 0.05 to 0.85 mole of an aromatic polyisocyanate per mole of the polyisocyanate. A stabilized non-yellowing type urethane polymer characterized by the use of the above is disclosed. In the publication, as a preferred embodiment, it is necessary to prevent the aromatic polyisocyanate from reacting only via the chain extender, and the polyfunctional hydroxy compound and the chain extender are first used with a non-yellowing isocyanate. It shows that a polyurethane polymer having good solvent resistance, water resistance, hydrolysis resistance and yellowing resistance can be obtained when reacted and then reacted with an aromatic polyisocyanate, claiming its superiority. However, in the case of synthetic leather and artificial leather, aromatic polyisocyanate reacts only through a chain extender, thereby providing excellent properties such as strength physical properties and coagulability, thereby obtaining a polyurethane resin suitable for the application. The polyurethane resin used in the present invention cannot be obtained from the polyurethane resin obtained by the method disclosed in the publication.

Japanese Patent Publication No. 55-19928 discloses a diisocyanate compound having an isocyanate group bonded to an aliphatic hydrocarbon in an amount of 30 to 45 mol% and a molecular weight of 500 to 30.
A solution of a dihydroxy compound having a molecular weight of 8 to 15 mol% and a low molecular weight dihydroxy compound having a molecular weight of 20 to 40 mol% using an appropriate solvent is subjected to solution polymerization. Also disclosed is a method for producing a dyeable polyurethane, which comprises introducing 10 to 20 mol% of a low molecular weight dihydroxy compound and performing a chain extension reaction.

According to the publication, as a preferred embodiment, as a first step, a dihydroxy compound having a molecular weight of 500 to 3000, a dihydroxy compound having a low molecular weight, and a diisocyanate compound having an isocyanate group bonded to an aliphatic hydrocarbon are used as an equivalent ratio of NCO / OH. A mixture obtained by reacting at least 1 is obtained, and as a second step, an aromatic diisocyanate and a low-molecular-weight dihydroxy compound are added, and a chain extension reaction is carried out, whereby a polyurethane having excellent dyeing properties and heat resistance is obtained. It shows that it is used for business and claims its superiority. However, because the low molecular weight dihydroxy compound used in the first step is a chain extender,
Not only is it inferior in flexibility, but the equivalent ratio of NCO / OH is 1 or more, and the reaction rate of the isocyanate group bonded to the remaining aliphatic hydrocarbon group is higher than that of the aromatic diisocyanate introduced in the second stage. It is difficult to obtain a smooth reaction due to the large difference between the two methods, and it is difficult to obtain the polyurethane resin used in the present invention industrially by analogy with the method disclosed in this publication.

[0013]

SUMMARY OF THE INVENTION The present invention relates to a method for producing a polymer, which comprises a polymer diol selected from the group consisting of polyester, polycarbonate, and polylactone as a main raw material, and a polyurethane obtained by an improved production method. Another object of the present invention is to produce a leather-like sheet having excellent cold resistance, heat resistance, durability, and light resistance.

[0014]

The present invention provides a polyester,
A polymer diol (A) selected from the group consisting of polycarbonate and polylactone and an organic diisocyanate (B)
1) with an intermediate diol (C) having a terminal OH obtained by reacting NCO / OH in an equivalent ratio of 0.3 to 0.97 with diphenylmethane 4,4'-diisocyanate (B2) a leather-like sheet material characterized in that a polyurethane skin layer obtained by reacting with the low molecular chain extender (D) is adhered to the surface of the base layer with a polyurethane-based adhesive; Further, an equivalent ratio of NCO / OH of the polymer diol (A) selected from the group consisting of polyester, polycarbonate and polylactone to the aliphatic or alicyclic organic diisocyanate (B1) is 0.1%.
An intermediate diol (C) having a terminal OH obtained by reacting in a quantitative relationship so as to be 3 to 0.97, diphenylmethane 4,4'-diisocyanate (B2) and a low molecular chain extender (D) A leather-like sheet-like material characterized in that a polyurethane skin layer obtained by reacting the above is bonded to the surface of a base layer with a polyurethane-based adhesive.

The polymer diol (A) constituting the polyurethane for the skin layer of the leather-like sheet of the present invention is selected from the group consisting of polyester, polycarbonate and polylactone. Its number average molecular weight is 400-3000, preferably 500-2000, more preferably 700-1500.
Is selected. If it is less than 400, the polyurethane resin tends to lose its flexibility or its texture is lowered. If it exceeds 3000, it is likely that the urethane group concentration is reduced, and its texture, flexibility and cold resistance Not only is it difficult to obtain a leather-like sheet having a good balance of heat resistance, durability and wet coagulability, but there are also problems in the industrial production of the polymer diol. As the polymer diol, polyester, polycarbonate, and polylactone can be used alone or as a mixture at an arbitrary ratio. Further, it is not limited to use a low-molecular diol having a molecular weight of less than 400 as long as it does not impair the object of the present invention.
Components that are usually used as chain extenders, such as low-molecular-weight linear diols such as ethylene glycol, butanediol and hexanediol, and aromatic diols such as xylylene glycol, should be substantially free of flexibility, cold resistance, etc. Preferred in terms of surface.

The polyester diol used in the present invention can be obtained, for example, by reacting a dibasic acid with a diol. Examples of the dibasic acid include aromatic dibasic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, sebacic acid, and brassic acid, aromatic dibasic acids such as isophthalic acid, terephthalic acid, and naphthalenedicarboxylic acid. One of the basic acids or a combination thereof can be used. Among them, aliphatic dibasic acids, particularly dibasic acids having a methylene chain length of 4 to 8, such as glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid and sebacic acid, are more preferably used. Examples of the diol include aliphatic alcohols such as ethylene glycol, propylene glycol, butanediol, neopentyl glycol, methylpentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, and dodecanediol which may be substituted with a lower alcohol. Diols, cyclohexane diol, alicyclic diols such as hydrogenated xylylene glycer, and one or a mixture of two or more kinds of aromatic diols such as xylylene glycer are used.
In particular, one or a mixture of two or more aliphatic diols having a carbon chain length of 4 to 9, such as butanediol, methylpentanediol, hexanediol, heptanediol, methyloctanediol, and nonanediol, are preferably used.

The polycarbonate diol can be obtained, for example, by reacting a carbonate compound with a diol. As the carbonate compound, dimethyl carbonate, diphenyl carbonate, ethylene carbonate and the like can be used. As the diol, ethylene glycol, propylene glycol, butanediol, neopentyl glycol, methylpentanediol, hexanediol, which may be substituted with a lower alcohol,
One or two or more aliphatic diols such as heptane diol, octane diol, nonane diol, decane diol and dodecane diol; alicyclic diols such as cyclohexane diol and hydrogenated xylylene glycer; and aromatic diols such as xylylene glycer. Mixtures of more than one kind are used, and among them, aliphatic diols, especially butane diol, methyl pentane diol, hexane diol, heptane diol, methyl octane diol, nonane diol and the like having an aliphatic diol having a carbon chain length of 4 to 9 are preferred. One type or a mixture of two or more types is suitably used.

The polylactone diol is, for example, poly-
ε-caprolactone diol, poly-trimethyl-ε-
Examples include caprolactone diol and poly-β-methyl-δ-valerolactone diol.

The organic diisocyanate (B1) is, for example, diphenylmethane-4,4'-diisocyanate,
Aromatic diisocyanates such as 2,4- or 2,6-tolylene diisocyanate, meta- or para-phenylene diisocyanate, 1,5-naphthylene diisocyanate, isophorone diisocyanate, cyclohexane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, hydrogenated MDI, etc. And the like are used. Among them, as the organic diisocyanate (B1) to be reacted with the polymer diol (A), asymmetric diisocyanates such as 2,4- or 2,6-tolylene diisocyanate and isophorone diisocyanate, and especially, isophorone diisocyanate is a leather-like sheet-like material. Isophorone diisocyanate is preferred because a polyurethane having excellent flexibility is obtained, and furthermore, isophorone diisocyanate is more preferred because a leather-like sheet having good softness and light resistance can be obtained.

The intermediate diol (C) having a terminal OH is a polymer diol (A) and an organic diisocyanate (B1) having an equivalent ratio of NCO / OH of 0.3 to 0.97, preferably 0.5 to 0.97. It is obtained by reacting in a quantitative relationship such that If the equivalent ratio of NCO / OH is less than 0.3, the molecular weight of the polymer diol (A) and the organic diisocyanate (B
Although it depends on the type of 1), the amount of urethane bond incorporated into the intermediate diol having a terminal OH is too small, or the molecular weight is too small, or the texture, flexibility, cold resistance, It is difficult to balance heat resistance, and the effect of the present invention cannot be sufficiently obtained. Also NC
If the equivalent ratio of O / OH exceeds 0.97, the amount of urethane bonds incorporated into the intermediate diol having terminal OH may be too large, depending on the molecular weight of the polymer diol (A) and the type of the organic diisocyanate (B1). Furthermore, because the molecular weight becomes too large, it is difficult to balance the feeling, flexibility, cold resistance and heat resistance of the leather-like sheet, and the effect of the present invention cannot be sufficiently obtained.

Examples of the chain extender (D) include ethylene glycol, propylene glycol, butanediol, neopentyl glycol, methylpentanediol, hexanediol, heptanediol, octanediol, nonanediol, and decane which may be substituted with a lower alcohol. Alicyclic diols such as diols, aliphatic diols such as dodecane diol, cyclohexane diol, hydrogenated xylylene glycer, aromatic diols such as xylylene glycer, and one or a mixture of two or more kinds such as diethylene glycol are used. Among them, aliphatic diols, especially ethylene glycol,
Butanediol has the texture, flexibility,
It is suitably used in terms of balance between cold resistance, heat resistance, and wet solidification.

Although the amount of the low molecular chain extender (D) is not particularly limited, it varies depending on its molecular structure, the molecular weight of the polymer diol (A), the type of organic diisocyanate, and the NCO / OH equivalent ratio. The equivalent ratio of (D) / (A) is 0.5 to 5 with respect to the polymer diol (A).
Among them, the texture of the leather-like sheet from which 1-3 were obtained,
It is often preferred in terms of flexibility, cold resistance, heat resistance and wet solidification.

The amount of diphenylmethane-4,4'-diisocyanate (B2) used is not particularly limited, and the viscosity of the polyurethane solution, the molecular weight of the polymer diol (A), the polymer diol (A) and the organic diisocyanate (B1)
NCO / OH equivalent ratio, the reaction solvent, the polymer diol (A), the water contained in the low molecular chain extender (D), etc., but usually the N from (B1) and (B2)
CO, polymer diol (A) and low molecular chain extender (D)
Ratio of NCO / OH is 0.95 to 1.2
Above all, it is often used at 0.97 to 1.1.

A catalyst is not always necessary when the polymerization method used in the present invention is carried out. However, catalysts used in the production of ordinary polyurethanes, for example, metal compounds such as titanium tetraisopropoxide, dibutyltin dilaurate and tin octate; Methylbutanediamine,
Tertiary amines such as 1,4-diaza (2,2,2) bicyclooctane can be used.

As the solvent for the polyurethane obtained by the method of the present invention, commonly used solvents such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, toluene, ethyl acetate, methyl ethyl ketone and tetrahydrofuran are used. The polyurethane obtained by the method used in the present invention is used in various additives used in conventional polyurethanes, for example, phosphorus-based compounds, flame retardants such as halogen-containing compounds, antioxidants, ultraviolet absorbers, pigments, dyes. , A plasticizer, a surfactant and the like can be added.

As the polyurethane for the adhesive, a polyurethane resin handbook [Nikkan Kogyo Shimbun (Showa 62)
)] On page 438 can be used. For example, polyester diols obtained from diols and dicarboxylic acids, diols of polylactone or polyvalerolactone, polycarbonate diol, polytetramethylene glycol, polypropylene glycol, a mixture of two or more kinds of polyether diols such as polyethylene glycol, Polyurethane comprising a main agent obtained by reacting a copolymer with an organic diisocyanate and a crosslinking agent is used.

Here, polyester diol or polycarbonate diol is ethylene glycol, 2-methyl-1,3-propanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, 1,6-
Using a diol such as hexanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, dodecanediol, diethylene glycol, neopentyl glycol, or the like, it can be obtained in the same manner as in the case of the polyurethane for the skin layer. it can.

The organic diisocyanate includes known aliphatic, alicyclic and aromatic diisocyanates having two isocyanate groups in the molecule. In particular, 4,4'-
Diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, 2,4-substituted or / and 2,6
Substituted tolylene isocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, cyclohexane diisocyanate, and the like. Among them, asymmetric diisocyanates, in particular, 2,4-substituted or / and 2,6-substituted tolylene diisocyanate, isophorone diisocyanate, or those containing these as a main component are often used.

With respect to a specific operation method for obtaining the above main agent, a known polyurethane-forming reaction technique is used. For example, the number average molecular weight is 600-5000, especially 8
A polymer diol of 00 to 1500 and a low molecular weight diol are mixed as required, and an organic diisocyanate is added in an amount such that the ratio of the isocyanate group to the number of active hydrogen atoms (NCO / OH) becomes 1 or less, and 50 to 120 ° C. For several hours. The reaction may be performed in the presence of an organic solvent inert to isocyanate groups. When the production process is carried out in the presence of an organic solvent, the final mixture often has a solid content of 10 to 90%.

In the present invention, a compound having more than two groups capable of reacting with a hydroxyl group is blended as a crosslinking agent with the main agent obtained above and adhered. Examples of the crosslinking agent used here include an organic polyisocyanate, an epoxy resin, and a mixture thereof, and an organic polyisocyanate is particularly preferable. As preferred organic polyisocyanates, compounds having three or more isocyanate groups in the molecule, for example, all hydroxyl groups of polyhydroxy compounds such as trimethylisopropane, glycerin and pentaerythritol can be obtained by converting tolylene diisocyanate, crisp diisocyanate, hexamethylene diisocyanate, There are compounds urethanized with diisocyanates such as supplemental lon diisocyanate, and dimers and trimers of these diisocyanates. The ratio of the main agent and the curing agent in the adhesive used in the present invention is not particularly limited,
Although it depends on the type of the base material, the type of the hardener, and the use of the leather sheet, the hardener / base agent is usually used in a weight ratio of 0.03 to 0.3 in terms of texture, peel strength, and the like. Many.

The leather-like sheet of the present invention can be produced, for example, by the following transfer method. First, a polyurethane solution for a skin layer is applied on release paper with a doctor knife, and dried with hot air at 80 to 120 ° C. Although the thickness of the film for the skin layer to be obtained varies depending on the final use, the solution concentration and the application amount are usually adjusted to 10 to 100 μm. Then, an adhesive polyurethane solution is applied onto the skin layer, and a base fabric is stuck at an appropriate gap of a laminating roll, followed by hot air drying at 80 to 120 ° C. Thereafter, aging is performed at 40 to 60 ° C for 2 to 4 days. Thereafter, the release paper is peeled off, and the surface is finished several times with a gravure roll as needed. The base fabric may be a synthetic fiber such as polyamide, polyester, vinylon, polyacrylonitrile, or the like, or an artificial fiber such as rayon, cupra, acetate, or the like, or a natural fiber such as silk, face,
Any of knitted fabrics, woven fabrics, nonwoven fabrics obtained from wool, hemp, and the like, and impregnated fabrics obtained by impregnating such fabrics with a synthetic resin can be used. The adhesive and / or the polyurethane for the skin layer may be colored using a pigment or a dye. Of course, it may be dyed after being made into a leather sheet.

[0032]

The leather-like sheet material of the present invention thus obtained has excellent flexibility, heat resistance, cold resistance, light resistance, etc., and is suitable for various uses such as clothing, shoes, furniture, vehicle interior materials, and miscellaneous goods. Useful. It is particularly useful for artificial leather and synthetic leather.

Although the mechanism of action is not clear, the polymer diol (A) and the organic diisocyanate (B1) have a specific composition ratio and a urethane group-containing terminal obtained under conditions substantially free of a chain extender. OH intermediate diol (C) is reacted with diphenylmethane- in the presence of a chain extender (D).
By reacting with a 4,4'-diisocyanate (B2), a chain extender (D) which is considered to form a hard segment component with an intermediate diol (C) having a terminal OH containing a urethane group which is considered to form a soft segment component )) And diphenylmethane-4,4'-diisocyanate (B2), so that the leather-like sheet having the polyurethane resin as a surface layer has the above-mentioned preferable characteristics because the polyurethane resin obtained has an appropriate microphase separation state. It is thought that it was granted.

[0034]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. Examples 1 to 6, Comparative Examples 1 to 7 (Production of Intermediate) Examples 1 to 7 and Comparative Examples 4 and 7
The polymer diol and diisocyanate shown in Table 1 were charged into a reactor and reacted at the temperature and time shown in Table 1 under a nitrogen stream to obtain an intermediate (C). After confirming that the isocyanate group had disappeared, the result of measuring the weight average molecular weight (in terms of polystyrene) of the intermediate (C) using GPC is also shown in Table 1.

[0035]

[Table 1]

The abbreviations in the table are: PNOA: a 65:35 (weight ratio) mixture of nonanediol and 2-methyloctanediol and a polyester diol having a number average molecular weight of 1,000 obtained from adipic acid. PHC: a polyester diol having a number average molecular weight of 1,000. Polyhexylene carbonate PTMG: Polytetramethylene glycol having a number average molecular weight of 1,000 MDI: Diphenylmethane-4,4′-diisocyanate TDI: Tolylene diisocyanate (80/20 of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate) IPDI: isophorone diisocyanate EG: ethylene glycol DMF: N, N'-dimethylformamide MEK: methyl ethyl ketone.

(Production of polyurethane for skin) The above-obtained intermediate or polymer diol was added to diisocyanate, ethylene glycol having the composition shown in Table 2 and DM as a solvent.
F was charged into the reactor, reacted at a predetermined temperature under a nitrogen stream for a predetermined time, cooled when no isocyanate group was found, and charged and dissolved with MEK. In Comparative Examples 3 and 4, the isocyanate groups remained even after the reaction was continued at 80 ° C. for 13 hours, and the solution viscosity was extremely low. Therefore, 2 parts by weight of dibutyltin dilaurate was added as a polymerization catalyst, and the mixture was further heated at 80 ° C. After continuing the reaction for 15 to 17 hours, cooling when the isocyanate group disappeared,
MEK was charged and dissolved to obtain a polyurethane solution. Viscosity (Poise) at 30 ° C. of the obtained polyurethane solution
And the weight average molecular weight (in terms of polystyrene) measured using GPC are shown in Table 2.

[0038]

[Table 2]

(Preparation of resin composition for skin layer) 120 parts by weight of the polyurethane solution obtained above, 15 parts by weight of DMF, M
15 parts by weight of EK, 30 parts by weight of DUT-4093 (trade name: manufactured by Dainichi Seika), 0.1 part by weight of citric acid, and 0.1 part by weight of Sanol LS770 (trade name: manufactured by Sankyo) as a color pigment at room temperature. After defoaming well, the mixture was defoamed to obtain a resin formulation for the skin layer.

(Manufacture of adhesive base) 600 parts by weight of PONA, 400 parts by weight of PTMG, 150 parts by weight of TDI, D
320 parts by weight of MF and 173 parts by weight of MEK were sufficiently reacted to obtain a polyurethane solution for a base material. (Preparation of resin composition for adhesive) 100 parts by weight of main agent, 30 parts by weight of coronate HL (trade name, manufactured by Nippon Polyurethane) as a curing agent, 0.1 part by weight of citric acid, SANOL LS
770 (trade name: manufactured by Sankyo Co., Ltd.) in an amount of 0.1 part by weight was thoroughly mixed at room temperature, and then defoamed to obtain a resin mixture liquid for a skin layer.

(Production of a leather-like sheet) A resin coating solution for a skin layer was dried on a release paper using a comma coater to a dry thickness of 3%.
The coating is applied so as to have a thickness of 0 μm and dried with hot air at 120 ° C. to obtain a film. Subsequently, a resin composition liquid for an adhesive was applied on the skin layer film so as to have a dry thickness of 50 μm,
After drying with hot air at 0 ° C., the raising surface of a raising cloth using polyester yarn as warp yarn and rayon yarn as weft yarn is overlapped, and then laminated with a 90 ° C. heat laminating roll. 40
After curing at 3 ° C. for 3 days, the release paper is peeled off to obtain a leather sheet.

(Evaluation) The obtained leather-like sheet was evaluated by the following test method. The results are shown in Table 3. Texture: 20 ° C and -10 by 10 panelists
In the atmosphere of ° C., the texture by touch was evaluated according to the following criteria. ◎ Extremely flexible and gentle touch, fully practicable. ○ Flexible and gentle touch, practical. △ Poor flexibility, impractical. × Inferior in flexibility and rough touch, impractical at all. -State after fade test: Using a long life light resistance tester (manufactured by Suga Test Instruments Co., Ltd.), carbon arc, 83 ° C, 10
The surface condition after 0 hour and the presence or absence of coloring were determined according to the following criteria. ◎ No change at all. ○ Some yellowing is observed, but there is no change in surface condition and there is no practical problem. △ The embossed pattern on the surface became thin, and a shining feeling was generated. C: The embossed pattern on the surface is extremely thin, and a large shine is generated. Some yellowing. -Test not conducted due to extremely poor texture.

[0043]

[Table 3]

Although the compositions of Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, and Example 3 and Comparative Example 3 were the same, respectively, (A) and (B1) were NCO / OH The intermediates (C) and (D) and (B2), which are obtained by reacting in a quantitative relation such that the equivalent ratio becomes 0.85, have a good texture, and the surface by fade A leather-like sheet having no change in state is obtained. On the other hand, any of the conventional methods in which (B1) and (B2) are reacted at once without passing through the intermediate (C) have poor texture at −10 ° C. or have an embossed pattern on the surface by a fade test. Of the method of the present invention is obvious.

In Example 3, since isophorone diisocyanate was used for the production of the intermediate (C), not only the texture but also the coloring by the fade test were not observed, and the effect of the present invention using isophorone diisocyanate as (B1) is clear. . Comparative Example 4 was obtained by reacting (D) and (B2) with the intermediate obtained by reacting in a quantitative relationship such that the equivalent ratio of NCO / OH was 1.17, but the texture was poor. In addition, there are disadvantages such as a thin embossed pattern on the surface and a feeling of shine. That is, in the production of the intermediate, the effect of the present invention in which the equivalent ratio of NCO / OH of (A) and (B1) is 0.97 or less is apparent.

Example 4 and Comparative Example 6 have the same composition.
Comparative Example 5 differs from Example 4 only in diisocyanate.
Had a good texture and slightly yellowed after the fade test, but there was no change in the surface state, and a result that was practically acceptable was obtained. However, in Comparative Examples 5 and 6, the texture was poor, and the effect of the present invention was clear.

In Example 5 and Comparative Example 7, (A) and (B1) in the production of the intermediate were changed so that the equivalent ratio of NCO / OH was reduced. The effect of the present invention for reacting the intermediates (C), (D) and (B2) obtained by reacting in a quantitative relationship such that the equivalent ratio becomes 0.6 is clear. On the other hand, Comparative Example 7 having an equivalent ratio of 0.4 had a poor texture, and was obtained by reacting (A) and (B1) in a quantitative relationship such that the equivalent ratio of NCO / OH was 0.4. When the obtained intermediate was reacted with (D) and (B2), the effect of the present invention was not clearly obtained.

In consideration of the result that the effect of the present invention could not be obtained when the equivalent ratio of NCO / OH was 1.17 in Comparative Example 4, (A) and (B1) of the present invention were compared with NC.
The effect of the method of obtaining the polyurethane resin via the intermediate (C) obtained by reacting at an equivalent ratio of O / OH of 0.3 to 0.97 is apparent.

[0049]

As described above, the leather-like sheet material of the present invention is excellent in texture, especially at low temperature, heat resistance, light resistance, etc., and is extremely useful as a material for clothing, shoes, bags, furniture, and vehicles. It is something.

Claims (2)

(57) [Claims] 1. A polymer diol (A) selected from the group consisting of polyester, polycarbonate and polylactone and an organic diisocyanate (B1) are mixed with NCO / 0
An intermediate diol (C) having a terminal OH obtained by reacting in a quantitative relationship such that the equivalent ratio of H becomes 0.3 to 0.97, diphenylmethane 4,4'-diisocyanate (B2) and a low molecular compound A leather-like sheet material characterized in that a polyurethane skin layer obtained by reacting with a chain extender (D) is adhered to the surface of a base layer with a polyurethane adhesive. 2. A polymer diol (A) selected from the group consisting of polyester, polycarbonate and polylactone and an aliphatic or alicyclic organic diisocyanate (B1) having an equivalent ratio of NCO / OH of 0.3 to 0.97.
The intermediate diol (C) having a terminal OH obtained by the reaction in such a quantitative relationship as described above is reacted with diphenylmethane 4,4'-diisocyanate (B2) and a low molecular chain extender (D). A leather-like sheet, wherein the polyurethane skin layer is adhered to the surface of the base layer with a polyurethane-based adhesive.