JP2005048118A - Polyurethane-based composition for coating film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyurethane-based composition with low viscosity, low odor, excellent in compatibility with a polyurethane resin and rapidly dissipating the odor of a solvent. <P>SOLUTION: This room temperature-curable polyurethane composition comprises a main component containing a compound having an isocyanate group, at least one kind curing component selected from an aromatic polyamine, a polyol, water and moisture, and a diluent, where the main component of the diluent is a 6-10C alicyclic hydrocarbon compound. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a polyurethane-based coating film composition that has a low odor during coating film formation and coating film drying, has a low viscosity, and is excellent in coating workability.

  Two-component room-temperature curable composition consisting of a main component mainly composed of an isocyanate group-terminated urethane prepolymer and a curing agent containing an active hydrogen compound, and a one-component moisture-curing component mainly composed of an isocyanate group-terminated urethane prepolymer Polyurethane elastomers obtained by reactive curing of water-soluble compositions with moisture in the air are used for a wide range of building materials such as waterproofing materials, flooring materials, anticorrosion materials, sealing materials, and elastic paving materials due to their excellent flexibility. Yes.

  The two-component room temperature curable composition comprises a main component mainly composed of an isocyanate group-terminated urethane prepolymer obtained by reacting a polyoxypropylene polyol and tolylene diisocyanate, a polyoxypropylene polyol, and 4,4′-methylenebis. The two-component type consisting of a curing agent mainly composed of (2-chloroaniline) is still mainstream.

  On the other hand, the one-pack type moisture curable composition comprises a liquid mainly composed of an isocyanate group-terminated urethane prepolymer obtained by reacting a polyoxypropylene polyol with 4,4′-diphenylmethane diisocyanate. There are a reaction curing type, a water curing type in which water is added to a liquid mainly composed of an isocyanate group-terminated urethane prepolymer obtained by reacting polyoxypropylene polyol with tolylene diisocyanate, and the like.

  In the conventional polyurethane coating film composition, in the two-pack type, for example, the above 4,4′-methylenebis (2-chloroaniline) is solid at room temperature, and therefore usually 30-50 in polyoxypropylene polyol. Used by dissolving in a concentration of mass%. This solution has a high viscosity, and a filler such as calcium carbonate is mixed with the curing agent. Therefore, a diluent (organic solvent) such as toluene, xylene, and aromatic hydrocarbons is used to reduce the viscosity of the curing agent. It was necessary to add 1 to 8% by mass.

  Further, for example, an isocyanate group-terminated urethane prepolymer obtained by reacting a polyoxypropylene polyol and 4,4′-diphenylmethane diisocyanate used in a one-component moisture-curable composition has a relatively high viscosity, and further has a carbonic acid content. In order to mix a filler such as calcium, it was necessary to add 3 to 20% by mass of the diluent as described above.

  However, such a diluent has a strong odor, and in order to maintain workability in winter, it is necessary to add a large amount of diluent to lower the viscosity of the composition. Moreover, since the solvent odor is difficult to be removed for a long time after construction, it is not preferable in terms of environmental hygiene.

  As a polyurethane-based coating composition that does not use a conventional organic solvent-based diluent as described above, for example, a solvent-free urethane coating material using a plasticizer is disclosed. Techniques using one or more selected from acid ester, aliphatic dibasic acid ester, phosphate ester, epoxy fatty acid ester, glycol ester, chlorinated paraffin, and petroleum are proposed. (See Patent Document 1).

In addition, as a method for adjusting a magnetic paint or the like that hardly causes aggregation, a technique using a mixed solution of toluene, methyl ethyl ketone, and cyclohexane as a solvent has been proposed (see Patent Document 2).
JP 2002-364128 A JP-A-8-67836

  However, in the method using a plasticizer as disclosed in JP-A-2002-364128, a compound having a boiling point of 200 ° C. or higher is usually used as the plasticizer. Since this compound has a lower vapor pressure than toluene and xylene, and the effect of reducing the viscosity is insufficient, there is a problem that workability at the time of coating film formation and drying of the coating film are inferior.

  In addition, the method of JP-A-8-67836 uses cyclohexane having a low odor as a solvent, but since it is a mixture containing a compound having a strong odor such as toluene and methyl ethyl ketone, the odor is not improved. Neither does it disclose an application to a polyurethane coating composition.

  The present invention has been made in view of the above-mentioned problems of the prior art, and provides a polyurethane-based coating film composition that has low odor, low viscosity, excellent compatibility with a polyurethane resin, and quick disappearance of solvent odor. With the goal.

  In order to achieve the above object, the composition for a polyurethane-based coating film of the present invention comprises a main ingredient component containing a compound having an isocyanate group, and at least one curing component selected from an aromatic polyamine, a polyol, water, and moisture. And a normal temperature curable polyurethane coating film composition containing a diluent, the main component of the diluent is an alicyclic hydrocarbon compound having 6 to 10 carbon atoms.

  Here, the alicyclic hydrocarbon compound is preferably an alicyclic hydrocarbon compound having an alkyl side chain, and the alicyclic hydrocarbon compound is more preferably ethylcyclohexane and / or methylcyclohexane. preferable.

  According to the polyurethane-based coating film composition of the present invention, since the alicyclic hydrocarbon compound having 6 to 10 carbon atoms is used as the main component of the diluent, it can be used as an aromatic diluent such as toluene or xylene. In comparison, there is less odor when the coating film is formed (at the time of application) and when the coating film is dried. Further, since the vapor pressure is sufficiently high, it is excellent in volatility, and the diluent does not remain in the coating film for a long time. Moreover, since it is excellent in compatibility with a main ingredient and a hardening | curing agent, it is excellent in dilution property, and even if it adds a little, the viscosity of the composition for polyurethane-type coating films can fully be reduced, and the workability | operativity at the time of coating film formation is also favorable. Further, the appearance of the coating film after the coating film formation is not deteriorated.

  In addition, general-purpose organic solvents such as toluene, xylene, aromatic mixed hydrocarbons, and aromatic hydrocarbons having 11 or more carbon atoms have strong odors and high toxicity, and are subject to organic solvent poisoning prevention regulations. However, the alicyclic hydrocarbon compound having 6 to 10 carbon atoms is not subject to the organic solvent poisoning prevention regulations and has high safety. Moreover, since it is an alicyclic hydrocarbon compound, its photochemical reactivity is low, and even if released into the atmosphere, it is unlikely to cause photochemical smog.

  In the present invention, the compound having an isocyanate group is preferably an isocyanate group-terminated urethane prepolymer obtained by reacting a polyether polyol with tolylene diisocyanate and / or 4,4'-diphenylmethane diisocyanate. The aromatic polyamine is preferably at least one selected from 4,4'-methylenebis (2-chloroaniline), dimethylthiotoluenediamine, and diethyltoluenediamine. The polyurethane-based coating composition of the present invention is not particularly limited to the polyurethane-based resin to be applied, and therefore can be applied to a polyurethane resin comprising the above-mentioned general-purpose main component and curing agent component.

  Moreover, in this invention, it is preferable that content of the said diluent is 3-15 mass% with respect to the said whole composition for polyurethane-type coating films. The alicyclic hydrocarbon compound having 6 to 10 carbon atoms used in the present invention is excellent in compatibility with ordinary polyurethane resins and has a large effect of reducing the viscosity. Therefore, even a small amount of 3 to 15% by mass is sufficiently added. Viscosity can be reduced.

  Furthermore, in the present invention, the polyurethane coating film composition is one of a two-component reaction curable type, a one-component moisture curable type, and a water curable type, and is any one of a waterproof material, a flooring material, and an anticorrosive material. It is preferable to be used as It does not specifically limit as a form of the polyurethane-type coating film composition of this invention, It can use suitably in any of a two-component reaction hardening type, a one-component moisture hardening type, and a water hardening type. Moreover, since there is little odor at the time of coating-film formation and coating-film drying, it is used especially suitably for the application | coating construction not only indoors but outdoors like a waterproofing material, a flooring material, and an anticorrosion material.

  According to the present invention, by using an alicyclic hydrocarbon compound having a specific carbon number as a diluent, a polyurethane-based coating suitable for waterproofing materials and flooring materials having low viscosity, low odor, and quick disappearance of solvent odor. A film composition can be provided.

Hereinafter, each component used for the urethane type coating film composition of this invention is demonstrated.
First, the main ingredient component only needs to contain a compound having an isocyanate group, but an isocyanate group-terminated urethane prepolymer is preferred. It does not specifically limit as a form of the composition for polyurethane type coating films, It can use for any of a two-component reaction curing type, a one-component moisture curing type, and a water curing type.

  In the case of the two-component reaction curable type, examples of the polyisocyanate used as a raw material for the isocyanate group-terminated urethane prepolymer used as the main agent include aromatic, aliphatic, and modified polyisocyanates having two or more isocyanate groups. However, tolylene diisocyanate is preferable from the viewpoint of the viscosity of the prepolymer to be obtained, curability, and mechanical strength of the cured coating film. Among these, tolylene diisocyanate having a 2,4-isomer content of 80% by mass or more is particularly preferable.

  The polyol used as the raw material for the isocyanate group-terminated urethane prepolymer used as the main component in the two-component reaction curable type is preferably a polyether polyol (polyoxyalkylene polyol), more preferably a polyoxypropylene polyol. The average number of functional groups of the polyol is preferably 2 to 4, more preferably 2 to 3, particularly preferably 2 to 2.5, and most preferably 2.1 to 2.4. When the average number of functional groups is less than 2, it is difficult to increase the molecular weight of the cured product, so that the mechanical strength of the cured coating film is insufficient. On the other hand, if it exceeds 4, the crosslinking density becomes too high, and the elongation performance of the cured coating film deteriorates.

  The polyol is preferably composed of a mixture of polyoxypropylene diol and polyoxypropylene triol, and the molar ratio is preferably 60/40 to 90/10. The molecular weight of the polyol is preferably 200 to 7000, particularly preferably 700 to 1500, as the molecular weight per hydroxyl group, from the balance of the viscosity of the prepolymer to be obtained, the strength of the cured coating film, and the elongation performance.

  In the isocyanate group-terminated urethane prepolymer, the ratio of polyisocyanate to polyol is preferably 1.8 to 2.5 in terms of equivalent ratio (molar ratio) (NCO / OH) of isocyanate group to hydroxyl group. Further, the isocyanate group content (NCO group content) in the isocyanate group-terminated urethane prepolymer is preferably 2 to 5% by mass for waterproofing materials, and preferably 4 to 8% by mass for flooring materials.

  As the curing agent in the two-component reaction curing type, 4,4′-methylenebis (2-chloroaniline), dimethylthiotoluenediamine, diethyltoluenediamine, and the like can be used, and when combined with a polyol having a relatively high molecular weight, Curable properties can be obtained.

  Polyols used for the curing agent are preferably polyether polyols, and particularly preferably polyoxypropylene polyols. 2-4 are preferable and, as for the functional group number of this polyol, 2-3 are more preferable. If the number of functional groups is less than 2, it is difficult to increase the molecular weight of the cured product, so that the curability is deteriorated and the mechanical strength of the cured coating film is insufficient. On the other hand, if it exceeds 4, the crosslinking density becomes too high, and the elongation performance of the cured coating film deteriorates.

  The hydroxyl value of the polyol is preferably 10 to 112 mgKOH / g, more preferably 16 to 56 mgKOH / g. If it is less than 10 mg KOH / g, the viscosity of the polyol becomes too high, and if it exceeds 112 mg KOH / g, the molecular weight is small, so the number of parts to be added to the curing agent is reduced, and as an alternative, the amount of plasticizer used is increased.

In the two-component reaction curing type, the equivalent ratio (molar ratio) (NCO / (NH ₂ + OH)) of the isocyanate group of the main component and the active hydrogen-containing group of the curing agent component is preferably 1.0 to 1.3.

  Further, a known curing catalyst that accelerates the urethanization reaction may be used. As the curing catalyst, organic acid lead, organic acid tin, tertiary amine compound and the like are used. In addition, the curing agent component may contain an additive selected from a plasticizer, a filler, a pigment, and a stabilizer.

  Plasticizers include dioctyl phthalate (bis (2-ethylhexyl) phthalate), dibutyl phthalate, dinonyl phthalate, diisononyl phthalate, dioctyl adipate, methyl esters of lard, methyl esters of coconut oil, chlorine Paraffin and petroleum plasticizers. Of these, dioctyl phthalate is particularly preferable. These plasticizers may be used but are preferably not used.

  As the filler, calcium carbonate, talc, clay, silica, carbon and the like can be used, and as the pigment, inorganic pigments such as chromium oxide and titanium oxide, and organic pigments such as phthalocyanine pigments can be used.

  Furthermore, stabilizers such as antioxidants, ultraviolet absorbers, and dehydrating agents that are generally used for polyurethane resins may be blended as necessary.

  On the other hand, in the case of the one-component curable type, it is preferable to use 4,4'-diphenylmethane diisocyanate as a polyisocyanate which is a raw material of the polyurethane prepolymer used as the main agent from the viewpoint of curability. Then, a liquid mainly composed of an isocyanate group-terminated urethane prepolymer obtained by reacting 4,4'-diphenylmethane diisocyanate and polyoxypropylene polyol is reacted and cured with moisture in the air. The NCO group content of the isocyanate group-terminated urethane prepolymer is preferably 0.3 to 2% by mass.

  In addition, for example, a water curing type in which water is added to a liquid mainly composed of an isocyanate group-terminated urethane prepolymer obtained by reacting a polyoxypropylene polyol and tolylene diisocyanate, and an isocyanate group is cured. A deamined type in which a latent curing agent such as a block amine is added to the terminal urethane prepolymer may be used.

  Next, the diluent used in the present invention will be described. In the present invention, a diluent whose main component is an alicyclic hydrocarbon compound having 6 to 10 carbon atoms is used.

  When the number of carbon atoms is 5 or less, the boiling point becomes low, the volatilization of the diluent is too fast during the formation of the coating film, and fine blisters and pinholes are likely to occur in the coating film. On the other hand, when the number of carbon atoms is 11 or more, the boiling point becomes high and the volatilization of the diluent becomes slow, so that an odor is likely to remain, and this tends to cause a decrease in gloss and curability of the coating film.

  Specific examples of such alicyclic hydrocarbon compounds having 6 to 10 carbon atoms include methylcyclopentane, ethylcyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane, butylcyclohexane, dimethylcyclohexane, methylethylcyclohexane, and propyl. Examples include cyclohexane and trimethylcyclohexane.

  Among these, alicyclic hydrocarbon compounds having an alkyl side chain are preferable, ethylcyclohexane and methylcyclohexane are more preferable, and ethylcyclohexane is particularly preferable.

  As shown in Table 1 below, the above-mentioned ethylcyclohexane and methylcyclohexane are examples of dioctyl phthalate (DOP), dibasic acid ester (DBE), which are examples of plasticizers, and diluents. Compared to aromatic mixed hydrocarbons (trade names: mineral terpenes, ipsol 150, etc.) and close to the boiling point of xylene and toluene as diluents, they are excellent in volatility. Therefore, the coating film can be dried in a short time, and the workability is also good.

  In addition, the alicyclic hydrocarbon compound having 6 to 10 carbon atoms has a smaller molecular weight than a naphthene hydrocarbon having 11 or more carbon atoms and a higher polarity than a chain paraffin hydrocarbon. Good solubility and great viscosity reduction effect. Moreover, since the specific gravity of ethylcyclohexane is 0.79 and is lower than 0.87 of xylene, the viscosity of the mixture can be further reduced with the same added parts by mass.

  Of the compounds in Table 1, diluents such as toluene, xylene, and aromatic mixed hydrocarbons are not preferable in terms of environmental hygiene because they have a strong odor and the solvent odor is difficult to escape for a long period of time.

  Further, diluents that are not subject to the aforementioned organic solvent poisoning prevention regulations include 2-ethylhexyl acetate, methyl caprylate, naphthene hydrocarbons having 11 or more carbon atoms, chain paraffin hydrocarbons, methyl-tert-butyl ether. However, all of them have strong odor, and naphthenic hydrocarbons and chain paraffinic hydrocarbons having 11 or more carbon atoms are insufficiently compatible with the urethane coating material.

  In addition to the alicyclic hydrocarbon compound having 6 to 10 carbon atoms, the diluent of the present invention may contain a small amount of other diluent for the purpose of raising the flash point, but does not contain it. Is preferred. Other diluents include 2-ethylhexyl acetate, methyl caprylate, methyl-tert-butyl ether, naphthenic hydrocarbons having 11 or more carbon atoms, and chained paraffinic carbonization that are not subject to the above organic solvent poisoning prevention regulations. Hydrogen and the like are preferable. Of these, naphthenic hydrocarbons having 11 or more carbon atoms and chain-like paraffinic hydrocarbons are more preferable, and the mixing amount is preferably 10% by mass or less based on the entire diluent.

  The diluent is preferably blended in an amount of 3 to 15% by mass, more preferably 5 to 10% by mass, based on the entire polyurethane-based coating film composition. If the blending amount is less than 3%, it is not preferable because the viscosity is not sufficiently reduced by the diluent. If it exceeds 15%, it takes time to dry the coating film. This is not preferable because it causes thinning of the meat.

  In the case of a two-component urethane coating material, the diluent can be mixed with either the main agent, the curing agent, or both. Moreover, you may add when mixing the two liquids to be used. In the case of a one-component moisture-curing urethane coating material, it may be mixed in advance with an isocyanate group-terminated urethane prepolymer, or may be added when used.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.
The polyurethane coating film compositions of Examples 1 to 6 and Comparative Examples 1 to 4 were adjusted by the following procedure.

<Composition for two-component waterproofing material>
Molecular weight 3000, polyoxypropylene triol 17 mass parts, molecular weight 2000, polyoxypropylene diol 68 mass parts, 15 mass parts tolylene diisocyanate (2,4-isomer 80 mass%) (NCO / OH ratio = 2. 03) was reacted, and an isocyanate group-terminated urethane prepolymer having an NCO group content of 3.6% by mass was obtained as a main agent.

In a melt mixture of 7.30 parts by mass of 4,4′-methylenebis (2-chloroaniline) and 21.04 parts by mass of polyoxypropylene diol having a molecular weight of 2000, 7.66 parts by mass of dioctyl phthalate and 60 parts by mass of calcium carbonate , 3 parts by mass of pigment paste and 1 part by mass of lead octylate (lead content: 24%) are used as a curing agent, and mass ratio of main agent / curing agent = 1/1 (NCO / (NH ₂ + OH) ratio = 1.13).

  The initial viscosity after 3 minutes of mixing in the mixture of the main agent and the curing agent (without addition of a diluent) was 8800 mPa · s.

  This mixture was diluted with a diluent at a blending ratio as shown in Table 2 to obtain compositions for polyurethane-based coating films of Examples 1 to 3 and 6 and Comparative Examples 1 to 4.

<Composition for one-part waterproofing material>
Isocyanate group-terminated urethane obtained by reacting 29.6 parts by mass of polyoxypropylene triol having a molecular weight of 12,000 with 2.4 parts by mass of 4,4′-diphenylmethane diisocyanate (NCO / OH ratio = 2.6). 15 parts by mass of ethylcyclohexane, 47 parts by mass of calcium carbonate, 6 parts by mass of pigment paste, and 0.3 parts by mass of bis (2-morpholinoethyl) ether are mixed with the prepolymer (NCO group content: 1.55% by mass). Thus, a polyurethane-based coating film composition of Example 4 was obtained.

<Composition for two-component flooring>
To 70 parts by mass of polyoxypropylene diol having a molecular weight of 1000, 26 parts by mass of tolylene diisocyanate (2,4-isomer 80% by mass) (NCO / OH ratio = 2.13) was reacted, and 4 parts by mass of dioctyl phthalate. Was added to obtain an isocyanate group-terminated urethane prepolymer having an NCO group content of 6.6% by mass as a main agent.

In a molten mixture of 9.9 parts by mass of 4,4′-methylenebis (2-chloroaniline) and 23.1 parts by mass of polyoxypropylene diol having a molecular weight of 2000, 7.7 parts by mass of dioctyl phthalate, 56 parts by mass of calcium carbonate, Using a liquid in which 3 parts by mass of pigment paste and 0.3 parts by mass of lead octylate (lead content: 24%) are mixed as a curing agent, the mass ratio of main agent / curing agent = 2/3 (NCO / (NH ₂ + OH) ratio = 1.08).

  In the mixture of the main agent and the curing agent (without addition of a diluent), the initial viscosity after 3 minutes of mixing was 8200 mPa · s.

  This mixture was diluted with a diluent at a blending ratio as shown in Table 2 to obtain a polyurethane-based coating film composition of Example 5.

Test example 1
About the composition for polyurethane-type coating films of Examples 1-6 and Comparative Examples 1-4, the performance as a waterproofing material and a flooring was evaluated by the following method. The results are summarized in Table 2.

<Viscosity>
The initial viscosity (unit: mPa · s) at 20 ° C. after 3 minutes of mixing of the main agent containing the diluent and the curing agent was measured.

<Odor>
In a laboratory at 23 ° C. and 50% RH, the mixture of the main agent, curing agent, and diluent was applied to a 600 mm square flexible plate with a gold spatula so as to be ² kg / m ² to form a coating film. The intensity of odor during work was judged by sensory sense. However, the determination was made in three stages: ○: almost no odor, Δ: slightly solvent odor, ×: strong solvent odor.

<Odor persistence>
The above coating film was cured under the conditions of 23 ° C. and 50% RH, and the nose was brought close to the cured coating film after 24 hours, and the odor was determined sensorially in the same three steps as described above.

<Appearance of coating surface>
The surface state of the cured coating film after 24 hours was visually observed and judged in three stages: ○: smooth, Δ: slightly flaky irregularities on the surface, and ×: flaky irregularities on the surface. In addition, when the compatibility at the time of dilution is bad, the coating film surface after hardening becomes difficult to finish smoothly.

  From the results of Table 2, in Examples 1 to 6, by using ethylcyclohexane as a diluent, a waterproof material having a low viscosity, excellent workability, little odor, and quick disappearance of solvent odor, coating film for flooring It can be seen that is obtained.

  On the other hand, in Comparative Example 1 using xylene as a diluent, the solvent odor during the coating operation was strong, and in Comparative Example 2 using the aromatic hydrocarbon, the solvent odor during the coating operation and after curing was strong. Further, in Comparative Example 3 using a naphthenic hydrocarbon having 11 or more carbon atoms as a diluent, the solvent odor during the coating operation and after curing is strong, and further, the compatibility of the diluent is somewhat poor and the coating film after curing is hardened. The surface condition was somewhat poor. Further, in Comparative Example 4 using a diluent mainly composed of linear hydrocarbons, the solvent odor during the coating operation was strong, and the solvent odor after curing was slightly recognized. Furthermore, the compatibility of the diluent was poor and the surface state of the coating film after curing was poor.

Test example 2
<Volatilization rate>
For the polyurethane-based coating film of Example 7 and Comparative Example 5, 5% each of ethylcyclohexane and xylene was added and mixed as a diluent to the mixture of the main agent and curing agent in Example 1 (no diluent). A composition was obtained. Each composition was coated as in Test Example 1 and cured under the conditions of 23 ° C. and 50% RH, and the weight change of the cured coating after 8 hours, 16 hours, 24 hours, 2 days, and 3 days was measured. did. Table 3 shows the results obtained by quantifying the initial weight as 105.

  From the results shown in Table 3, it can be seen that Example 7 using ethylcyclohexane is faster to dry than Comparative Example 5 using xylene, and is excellent in drying property as a diluent.

  The composition for polyurethane-based coating film of the present invention has low viscosity, little odor, excellent compatibility with polyurethane resin, and fast disappearance of solvent odor, so it is suitable for applications such as waterproofing materials, flooring materials, anticorrosion materials, etc. Available.

Claims (7)

  A room temperature curing type polyurethane-based coating film composition comprising a main ingredient component containing a compound having an isocyanate group, at least one curing component selected from aromatic polyamines, polyols, water and moisture, and a diluent. In Claim 1, The main component of the said diluent is a C6-C10 alicyclic hydrocarbon compound, The composition for polyurethane-type coating films characterized by the above-mentioned.   The polyurethane-based coating film composition according to claim 1, wherein the alicyclic hydrocarbon compound is an alicyclic hydrocarbon compound having an alkyl side chain.   The polyurethane-based coating film composition according to claim 1, wherein the alicyclic hydrocarbon compound is ethylcyclohexane and / or methylcyclohexane.   The compound according to any one of claims 1 to 3, wherein the compound having an isocyanate group is an isocyanate group-terminated urethane prepolymer obtained by reacting a polyether polyol with tolylene diisocyanate and / or 4,4'-diphenylmethane diisocyanate. The composition for polyurethane-type coating films of description.   The polyurethane according to any one of claims 1 to 4, wherein the aromatic polyamine is at least one selected from 4,4'-methylenebis (2-chloroaniline), dimethylthiotoluenediamine, and diethyltoluenediamine. System coating composition.   The composition for a polyurethane-based coating film according to any one of claims 1 to 5, wherein a content of the diluent is 3 to 15% by mass with respect to the entire composition for a polyurethane-based coating film.   The polyurethane-based coating film composition is one of a two-component reaction curable type, a one-component moisture curable type, and a water curable type, and is used as any of a waterproof material, a flooring material, and an anticorrosive material. The composition for polyurethane-type coating films as described in any one of -6.