JP3267727B2 - Thermoplastic polyurethane resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic polyurethane resin composition having excellent dispersibility of fine magnetic particles and useful as a binder for a magnetic recording medium capable of being filled at high density.

[0002]

2. Description of the Related Art Conventionally, as binders for magnetic recording media, ethyl cellulose, nitrocellulose, polyvinylidene chloride resin, vinyl chloride-vinyl acetate copolymer, styrene-butadiene copolymer, polymethyl methacrylate resin, Vinylidene chloride-methyl methacrylate copolymers, polyurethane resins, epoxy resins, polyester resins, and the like have been used.

However, data tapes for computers,
At present, the performance is not sufficient for applications requiring high performance such as floppy disks and video tapes. In particular, in recent years, the use of high-grade video tape has been accelerated, and a magnetic recording medium capable of high-density recording for recording and reproducing clear sound and images has been demanded.

[0004] As a measure for increasing the density, magnetic powder has been made finer and higher in magnetic force, and the tendency to increase the packing density of the magnetic powder in the magnetic layer has been increasing. However, with the increase in specific surface area due to the micronization of the magnetic powder as described above and the increase in cohesive force due to the high magnetic force, the conventional binder as described above does not have a sufficient function of dispersing the magnetic powder, and the Although the function has been entrusted to a dispersant such as a phosphoric acid compound, a system in which a dispersant is blended with a binder adversely affects the durability of the magnetic layer such as generation of bleed in the case of long-term use.

[0005] In order to solve the above-mentioned problems, a hydrophilic polar group such as a sulfonic acid group, a hydroxyl group, a carboxyl group, and a phosphoric acid group is introduced into a binder to improve the affinity with magnetic powder for a high dispersion function. Has been proposed. (JP-B-58-41565, JP-A-57-92422)
JP-A-59-30235, JP-A-59-1546
Nos. 33, 60-15473 and 60-20
Among these, binders containing a sulfonic acid group have the best dispersibility of magnetic powder and are promising.

[0006]

However, the above-mentioned binder containing a sulfonic acid group is expensive, and is generally produced by solution polymerization using a known organic solvent as a reaction medium. Therefore, the product shape is liquid (varnish-like), and the solid content as an active ingredient is only a part of the product. Therefore, when the product is transported, the transport cost becomes high, and there is also a safety problem since the product is transported in the presence of a flammable organic solvent. In addition, since the reaction solvent used for the solution polymerization is substantially a solvent for the magnetic coating material, a solvent suitable for a solvent recovery device used in manufacturing a magnetic recording medium must be used as the reaction solvent. It is difficult to produce a binder by changing the above.

For the above reasons, binders for solid-state magnetic recording media have been desired, and are disclosed in JP-B-58-8053, JP-B-61-231050, and JP-B-3-1364.
No. 8 and the like, it has been proposed that the uniform dispersibility of the magnetic powder,
A solid binder for a magnetic recording medium satisfying high filling properties, that is, low porosity and high surface smoothness during coating has not been obtained. The present inventors have found that a specific thermoplastic polyurethane resin composition is promising as a binder for a solid-state magnetic recording medium, and have accomplished the present invention.

[0008]

That is, the present invention relates to a polyester polyol having an average molecular weight of 500 to 2,000, wherein a ratio of an aromatic dicarboxylic acid to an aliphatic dicarboxylic acid in an acid component of the polyester polyol is a molar ratio. (Aromatic dicarboxylic acid) / (aliphatic dicarboxylic acid)
A thermoplastic polyurethane obtained by reacting a polyester polyol having a molecular weight of 5/95 to 90/10 with a low molecular weight diol having a molecular weight of less than 500 and an organic diisocyanate, wherein the polymer has a metal sulfonate group of 10 / per 10 １０００1000 equivalents / 10 ⁶ g, and the urethane group concentration of the polymer is from 1500 to
A thermoplastic polyurethane resin composition having 3000 equivalents / 10 ⁶ g, wherein the thermoplastic polyurethane contains a higher fatty acid metal salt in an amount of 0.01 to 1.0% by weight based on the thermoplastic polyurethane. Things.

The polyester polyol which is a raw material of the thermoplastic polyurethane resin in the present invention has an average molecular weight of 5
Must be between 2000 and 2000. Average molecular weight of 50
If it is less than 0, the thermoplastic polyurethane resin loses its flexibility and is not practical. If the average molecular weight exceeds 2,000, the melt viscosity of the polyester polyol itself increases and the fluidity decreases, which makes the production difficult and the crystallinity of the polyester polyol forming the soft segment of the thermoplastic polyurethane increases. Is reduced.

In the polyester polyol of the present invention, the ratio of the aromatic dicarboxylic acid to the aliphatic dicarboxylic acid in the acid component is a molar ratio of (aromatic dicarboxylic acid) / (aliphatic dicarboxylic acid) = 5/95. ~
90/10, preferably 30/70 to 70/30. When the above ratio is less than 5/95, the obtained thermoplastic polyurethane resin becomes soft and, for example, in the case of pellets, so-called "blocking" in which the pellets stick to each other occurs, which is not practical in terms of production and handling of products. In addition, blocking can be prevented by increasing the urethane group concentration of the thermoplastic polyurethane to increase the urethane group concentration of the thermoplastic polyurethane itself in order to prevent this blocking, but on the contrary, the solvent solubility is reduced, or even when dissolved in a solvent, the blocking is also used. Therefore, the compatibility with other resins such as vinyl chloride resin decreases, and as a result, high dispersion and high filling of the magnetic powder cannot be realized.

On the other hand, if the above ratio exceeds 90/10, the rigidity of the polyester polyol itself increases, resulting in a high softening point,
Not only does the production of thermoplastic polyurethane resin become difficult due to high viscosity, but also the solubility of the obtained thermoplastic polyurethane resin in solvent and the compatibility with other resins are reduced, so that high dispersion and high filling of magnetic powder cannot be realized.

As the aromatic dicarboxylic acid constituting the polyester polyol used in the present invention, terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalic acid and the like are used. P-oxybenzoic acid, p-
Aromatic oxycarboxylic acids such as (hydroxyethoxy) benzoic acid, and tri- and tetra-aromatic carboxylic acids such as trimellitic acid and pyromellitic acid can also be used in combination. On the other hand, succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid and the like are used as the aliphatic dicarboxylic acid. Further, as described later, an aromatic or aliphatic dicarboxylic acid having a sulfonic acid metal base can also be used.

As the glycol component, ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-
Hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 2,2,4-
Examples include trimethyl-1,3-pentanediol, 1,4-cyclohexanedimethanol, ethylene oxide adduct and propylene oxide adduct of bisphenol A, and ethylene oxide adduct and propylene oxide adduct of hydrogenated bisphenol A. Further, tri- and tetraols such as trimethylolethane, trimethylolpropane, glycerin and pentaerythritol may be used in combination.

The low molecular weight diol used in the present invention includes ethylene glycol, 1,4-butanediol,
6-hexanediol, propylene glycol, 1,3
-Propanediol, 1,5-pentanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanedimethanol, 1,4-bis (2-hydroxyethoxy ) Benzene and the like. These low molecular weight diols may be used alone or in combination of two or more.

The organic diisocyanate used in the thermoplastic polyurethane resin of the present invention includes 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-phenylene diisocyanate, diphenylmethane diisocyanate, m-phenylene diisocyanate, hexamethylene Diisocyanate, tetramethylene diisocyanate, 3,3'-dimethoxy-4,4'-
Biphenylene diisocyanate, 2,4-naphthalene diisocyanate, 3,3'-dimethyl-4,4-biphenylene diisocyanate, 4,4'-diphenylene diisocyanate, 4,4'-diisocyanate-diphenyl ether, 1,5-naphthalene diisocyanate, p
-Xylene diisocyanate, m-xylene diisocyanate, 1,3-diisocyanatomethylcyclohexane, 1,4-diisocyanatomethylcyclohexane,
4,4′-diisocyanatodicyclohexane, 4,
4'-diisocyanate dicyclohexylmethane, isophorone diisocyanate, etc.
Species or two or more species may be used in combination.

The thermoplastic polyurethane resin in the present invention may contain 10 to 1000 equivalents / 10 ⁶ g of a metal sulfonic acid base per polymer. If the amount of the metal sulfonate group per polymer is less than 10 equivalents / 10 ⁶ g, the dispersion of the magnetic particles becomes poor, and high packing properties cannot be obtained. In addition, the metal sulfonate base per polymer is 1000 equivalent / 1.
0 exceeds ⁶ g When become solvent solubility of the thermoplastic polyurethane resin is poor, and those lacking in practicality.

The thermoplastic polyurethane resin in the present invention is obtained by reacting with a polyester polyol, a low molecular weight diol and an organic diisocyanate, and any component may contain a metal sulfonate group. Some or all of these have a metal sulfonate base.

The polyester polyol having a sulfonic acid metal base preferably has a part of the acid component as a dicarboxylic acid having a sulfonic acid metal base. The dicarboxylic acid having a sulfonic acid metal base may be either an aromatic dicarboxylic acid or an aliphatic dicarboxylic acid.

The dicarboxylic acid component containing a sulfonic acid metal base includes 5-sodium sulfoisophthalic acid,
5-potassium sulfoisophthalic acid, 2-sodium sulfoterephthalic acid, 2-potassium sulfoterephthalic acid, and the like. The copolymerization amount of the dicarboxylic acid component containing these sulfonic acid metal bases is 0.1 to the total carboxylic acid component.
The molar ratio of the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid is (aromatic dicarboxylic acid) / (aliphatic dicarboxylic acid) = 5/95. ~ 90/10, preferably 30/7
Must be 0-70 / 30.

The polyester polyol containing the sulfonic acid metal base may be one kind or two or more kinds. Moreover, you may use together with the polyester polyol which does not have a sulfonic acid metal base. However, also in this case, the molar ratio of the aromatic dicarboxylic acid to the aliphatic dicarboxylic acid in the acid component of the entire polyester polyol is (aromatic dicarboxylic acid) / (aliphatic dicarboxylic acid) = 5/95 to 9
0/10, preferably 30/70 to 70/30.

The urethane group concentration of the thermoplastic polyurethane resin in the present invention must be 1200 to 3000 equivalent / 10 ⁶ g per polymer. The urethane group concentration is represented by the following equation when, for example, 4,4′-diphenylmethane diisocyanate (hereinafter abbreviated as MDI) is used as the organic diisocyanate. Urethane group concentration = {(MDI charged amount / total raw material charged amount)}
125｝ × 10 ⁶ (equivalents / 10 ⁶ g)

When the urethane group concentration is less than 1200 equivalents / 10 ⁶ g, the obtained thermoplastic polyurethane resin becomes soft, and the pellets are remarkably blocked, which is not practical in production and handling. 3000 equivalents /
When the amount exceeds 10 ⁶ g, blocking is eliminated, but the solvent solubility of the resin and the compatibility with other resins are reduced, and as a result, high dispersion and high filling of the magnetic powder cannot be realized.

The method for producing a thermoplastic polyurethane resin in the present invention may be carried out by a known method, for example, a bulk polymerization method in which all the raw materials are rapidly mixed, and the mixture is heated and polymerized on a conveyor belt, by a single-shaft or multi-shaft extractor. A melt polymerization method in which polymerization is performed while kneading can be used. In this case, the desirable compounding ratio is NC of organic diisocyanate.
O group / Total O of polyester polyol and low molecular weight diol
H group = 0.5 to 1.5, preferably 0.8 to 1.2.

In the production of the thermoplastic polyurethane resin of the present invention, a catalyst can be used if necessary. Examples of the catalyst include nitrogen-containing compounds such as triethylamine and triethylenediamine, and organometallic compounds such as dibutyltin dilaurate and tin octylate.

The thermoplastic polyurethane resin composition of the present invention contains a higher fatty acid metal salt in an amount of from 0.01 to 0.01% per polymer.
It must contain 1.0% by weight. In the present invention, the higher fatty acid metal salt has a function as an antiblocking agent. That is, in the case of the thermoplastic polyurethane resin alone according to the present invention, blocking does not occur around room temperature, but blocking does not occur under a high temperature atmosphere (for example, 60 ° C. or higher) in one of the manufacturing steps such as drying and curing steps. Absent. However, when the higher fatty acid metal salt is contained in an amount of 0.01% by weight or more based on the thermoplastic polyurethane resin, the occurrence of blocking can be prevented even in the high-temperature atmosphere as described above. However, when the content of the higher fatty acid metal salt is 0.
If the amount is less than 01% by weight, the effect of the addition of the higher fatty acid metal salt is not observed, and blocking occurs. When the content of the higher fatty acid metal salt exceeds 1.0% by weight, blocking in a high-temperature atmosphere can be prevented. However, when a magnetic tape or the like is manufactured using this, clogging of a magnetic paint filter filter becomes remarkable. Not practical.

The higher fatty acid metal salt used in the present invention is a metal salt of a saturated fatty acid having 14 to 30 carbon atoms,
Preferred higher fatty acid metal salts include calcium stearate, magnesium stearate, zinc stearate, magnesium lignocerate, zinc lignocerate, calcium montanate, magnesium montanate, zinc montanate, and the like. These can be used alone or in combination of two or more.

A known method is employed for the method of containing the higher fatty acid metal salt in the thermoplastic polyurethane resin. For example, a higher fatty acid metal salt is mixed with any of the raw materials of the thermoplastic polyurethane resin, and the thermoplastic polyurethane resin and the higher fatty acid metal salt are blended using a method or a blender or the like which is contained in the resin during the polymerization of the thermoplastic polyurethane. And a method of kneading and blending a thermoplastic polyurethane and a higher fatty acid metal salt by a two-wheel extruder or the like.

The thermoplastic polyurethane resin composition of the present invention can be used in a desired shape such as a pellet, a flake, a sheet, or the like. However, considering the solubility in a solvent in a paint production process, the specific surface area of the resin is reduced. A wide, easily dissolvable pellet is desirable.

The thermoplastic polyurethane resin composition according to the present invention may optionally contain a plasticizer such as dibutyl phthalate and triphenyl phosphate, dioctyl sulfo-sodium succinate, t-butyl phenol-polyethylene ether, ethyl naphthalene-sodium sulfonate. Lubricants such as zinc lauryl succinate stearate, soybean oil lecithin and silicone oil, various antistatic agents, ultraviolet absorbers such as substituted benzotriazoles, antioxidants such as phenol derivatives, and hydrolysis prevention of carbodiimides Agents can also be added.

As the binder for the magnetic recording medium according to the present invention, together with the thermoplastic polyurethane resin composition of the present invention, other commonly used polyurethane resins, vinyl chloride-vinyl acetate copolymer, ethyl cellulose, nitro Cellulosic or other cellulosic resins, polyester resins, epoxy resins, phenoxy resins, thermosetting resins or reactive resins such as acrylonitrile-butadiene copolymers and unsaturated prepolymers, such as urethane acrylic type, polyester acrylic dip, or As the functional monomer, an electron beam or ultraviolet curable resin such as a urethane acrylic type, a phosphoric acid ester acrylic type, or an aryl type can be used in combination.

The fine magnetic particles used in the present invention include γ-Fe ₂ O ₃ and CrO having a spinel structure.
₂ , cobalt ferrite (CoO, Fe ₂ O ₃ ), cobalt-adsorbed iron oxide, ferromagnetic Fe—Co—Ni-based alloy, and the like.

The thermoplastic polyurethane resin composition according to the present invention can be used in addition to a binder for a magnetic recording medium, a paint, an adhesive, a sealing agent, a waterproofing agent, a flooring agent, an artificial leather, a fiber treatment agent, an elastic fiber, a cushioning material, It can be used for sheets, belts, films, rolls, gears, solid tires, vibration-proof materials, tubes, packing materials, shoe soles, and the like.

[0033]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. The “parts” in Examples and Comparative Examples
Is "parts by weight" unless otherwise specified. The reduced viscosity of the thermoplastic polyurethane resin was measured at 30 ° C. in a phenol / tetrachloroethane (6: 4 weight ratio) mixed solvent.

(1) Synthesis Example of Polyester Polyol Containing Sulfonate Metal Base In a reaction vessel equipped with a thermometer, a stirrer, and a condenser for distilling, 43500 parts of terephthalic acid, 39300 parts of isophthalic acid, and 114600 parts of adipic acid 7400 parts of 5-sodium sulfoisophthalic acid, 42600 parts of ethylene glycol, 87 parts of neopentyl glycol
900 parts, 1,4-cyclohexanedimethanol
100 parts, 6.0 parts of tetrabutyl titanate were charged,
The esterification reaction was carried out at 180 to 230 ° C for 5 hours, and then the pressure of the reaction system was reduced to 5 mmHg over 30 minutes, and the temperature was raised to 240 ° C during this time. 0.3 mmHg, 24
The polycondensation reaction was performed at 0 ° C. for 10 minutes. The OH value of the obtained polyester was 79.3 mgKOH / g and the number average molecular weight was 1
414. The composition was as follows from NMR analysis and the like. Terephthalic acid 20 mol%, isophthalic acid 1
8 mol%, 5-sodium sulfoisophthalic acid 2 mol%, adipic acid 60 mol%, ethylene glycol 35 mol%, neopentyl glycol 35 mol%, 1,4-cyclohexanedimethanol 30 mol%.

The polyester polyols (B) to (E) shown in Table 1 were obtained by the same production method.

(2) Evaluation of Dispersibility of Magnetic Powder 12 parts of thermoplastic polyurethane resin composition 18 parts of vinylite VAGH (manufactured by UCC) 120 parts of γ-Fe ₂ O ₃ containing Co 135 parts of methyl ethyl ketone 135 parts of toluene 135 parts

After the mixture having the above composition was kneaded for 5 hours using a paint shaker, 12 parts of Coronate-L (manufactured by Nippon Polyurethane), a polyisocyanate, was further added as a curing agent, and the mixture was further mixed for 30 minutes. The obtained magnetic paint was applied on a polyethylene terephthalate film having a thickness of 50 μm using a doctor blade having a gap of 50 μm, and the solvent was removed by drying. The uniform dispersibility, filling rate, and surface smoothness of the magnetic powder of the obtained magnetic coating film were evaluated as follows.

Uniform dispersibility: The surface gloss of the magnetic coating film was measured with a gloss meter and evaluated. Filling rate: The magnetic coating film was immersed in silicone oil, and the porosity of the magnetic coating film was determined from the amount of silicon oil impregnated and evaluated. Surface smoothness: The surface roughness of the magnetic coating film was measured using a stylus system and evaluated.

Example 1 Polyester polyol (A), MDI, and propylene glycol in Table 1 were treated at 100 ° C., 50 ° C., respectively.
The liquid was fed from the storage tank stored at 25 ° C. using a gear pump at the following liquid feed rate, and a twin-screw extruder (L) having a screw diameter of 30 mm was used.
/ D = 40), and the thermoplastic polyurethane was continuously melt-polymerized while kneading under a temperature condition of a final resin temperature of 230 ° C. Polyester polyol (A): 108.7 parts / minute Propylene glycol: 5.8 parts / minute MDI: 36.0 parts / minute

The molten thermoplastic polyurethane resin is discharged in a strand form from the die of a twin-screw extruder, water-cooled with a cooling bath, pelletized by a strand cutter, and then the pellets are fed by air to a Nauter mixer (Hosokawa Micron) having an internal volume of 100 L. 50,000 parts of pellets, and then 10 parts of calcium stearate (0.02% by weight per polymer) was added.
The mixture was dried and cured for 30 hours while stirring under a nitrogen stream at ℃ to obtain a thermoplastic polyurethane resin composition in the form of pellets. The content of the metal sulfonate group in the obtained thermoplastic polyurethane resin composition was 65 equivalent / 10 ⁶ g, the urethane group concentration was 1900 equivalent / 10 ⁶ g, and the reduced viscosity (η _SP
/ C) was 1.06. The obtained thermoplastic polyurethane resin composition is dried and cured (60 ° C.).
There was no blocking.

The surface gloss, porosity and surface roughness of the magnetic coating film using this resin composition were 9 as shown in Table 2.
Good values of 1, 21.0% and 0.023 μm were obtained.

Examples 2 to 7 A thermoplastic polyurethane resin composition was obtained in the same manner as in Example 1 except that the composition of the raw materials, the urethane group concentration, the type and the content of the higher fatty acid metal salt were changed as shown in Table 2. . The obtained thermoplastic polyurethane resin composition was not blocked even in an atmosphere at 60 ° C., and the surface gloss, porosity and surface roughness of the magnetic coating film using these resins were all good as shown in Table 2. Value.

Comparative Example 1 A thermoplastic polyurethane resin composition was prepared in the same manner as in Example 1 except that only the composition ratio was changed so that the urethane group concentration was 1190 equivalent / 10 ⁶ g. I got something. The surface gloss, porosity, and surface roughness of the magnetic coating film using this resin composition are good as shown in Table 2, but pellets of the obtained thermoplastic polyurethane resin composition are 6 pellets.
It was extremely blocked in an atmosphere of 0 ° C., and handling was difficult.

Comparative Example 2 A thermoplastic polyurethane resin composition was prepared in the same manner as in Example 1 except that only the composition ratio was changed so that the urethane group concentration was 3200 equivalent / 10 ⁶ g. I got something. The obtained thermoplastic polyurethane resin composition was prepared using methyl ethyl ketone / toluene (1/1 /
1 weight ratio) It was insoluble in the mixed solvent.

Comparative Example 3 A thermoplastic polyurethane resin having the same composition as in Example 1 but without adding calcium stearate was used in the same manner as in Example 1. The surface gloss, porosity and surface roughness of the magnetic coating film using this resin are good as shown in Table 2, but the pellets of the obtained thermoplastic polyurethane resin composition are significantly blocked at 60 ° C. atmosphere. And it was difficult to handle.

Comparative Example 4 A thermoplastic polyurethane resin composition was obtained in the same manner as in Example 1, except that the amount of calcium stearate was changed to 1.2% by weight. The surface gloss, porosity, and surface roughness of the magnetic coating film using this resin composition were good as shown in Table 2, and there was no blocking at 60 ° C. in the atmosphere. The blockage was remarkable.

Comparative Example 5 As the polyester polyol (D) shown in Table 1 (the molar ratio of aromatic / aliphatic acid component is 2/98), 3-methyl-1,5-pentanediol was used as the chain extender. A thermoplastic polyurethane resin composition was obtained in the same manner as in Example 1 at a composition ratio at which the urethane group concentration was 2820 equivalent / 10 ⁶ g. The surface gloss, porosity, and surface roughness of the magnetic coating film using this resin composition obtained good values as shown in Table 2, but the obtained thermoplastic polyurethane resin composition pellets were markedly blocked and difficult to handle. Met.

Comparative Example 6 A thermoplastic polyurethane resin composition was obtained in the same manner as in Example 1 except that (E) (containing no metal sulfonate group) in Table 1 was used as the polyester polyol. The surface gloss, porosity and surface roughness of the magnetic coating film using this resin composition were poor as shown in Table 2.

[0049]

[Table 1] ISN in Table 1 indicates 5-sodium sulfoisophthalic acid.

[0050]

[Table 2] In Table 2, PG is propylene glycol, MPG
Represents 2-methyl-1,3-propanediol, MPD represents 3-methyl-1,5-pentadiol, St-Ca represents calcium stearate, and St-Mg represents magnesium stearate.

[0051]

By using the thermoplastic polyurethane resin composition of the present invention, it is possible to obtain a binder for a magnetic recording medium which is excellent in dispersibility of magnetic particles at a low cost, and as a result, the cost is low. A high-density magnetic recording medium can be obtained, which greatly contributes to industry.

Continuation of the front page (51) Int.Cl. ⁷ identification code FI G11B5 / 702 G11B5 / 702 (56) References JP-A-59-6210 (JP, A) JP-A-62-119728 (JP, A) JP-A-4-356722 (JP, A) JP-A-63-206910 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 75/04-75/12 C08G 18/00 -18/87 C08K 5/09 C09D 5 / 23,175 / 06 G11B 5/702

Claims (1)

(57) [Claims] 1. An average molecular weight of 500 to 2,000, and a molar ratio of aromatic dicarboxylic acid to aliphatic dicarboxylic acid in the acid component is (aromatic dicarboxylic acid) / (aliphatic dicarboxylic acid) = 5/95 to 90. A thermoplastic polyurethane obtained by reacting a polyester polyol having a molecular weight of less than 500 with a low molecular weight diol having a molecular weight of less than 500 and an organic diisocyanate, wherein the polyurethane has a metal sulfonate base content of 10 to 1000 equivalents / 10 1 polymer / 10.
⁶ g, and the urethane group concentration is 120
A thermoplastic polyurethane having a weight of 0 to 3000 equivalent / 10 ⁶ g, wherein the thermoplastic polyurethane contains a higher fatty acid metal salt in an amount of 0.01 to 1.0% by weight based on the thermoplastic polyurethane. Polyurethane resin composition.