Two-component curing polyurethane composition

Abstract

To provide a two-pack curable polyurethane composition having an excellent pot life.SOLUTION: The two-pack curable polyurethane composition contains a curing agent, a main agent, and a reaction retarder. The curing agent contains a polyisocyanate component containing an allophanate derivative of xylylene diisocyanate and a metal catalyst, the main agent contains a polyol component, and the reaction retarder contains a phosphate ester. The ratio of the phosphate ester is 4 to 50 moles (inclusive) relative to 1 mole of a metal of the metal catalyst.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a two-component curing polyurethane composition. [Background technology]

[0002] The two-component curing polyurethane composition contains polyisocyanate (curing agent) and polyol (main component). A polyurethane resin is formed by a urethanization reaction of the two-component curing polyurethane composition. The polyurethane resin is used, for example, as a paint or adhesive.

[0003] Polyisocyanate (curing agent) is produced, for example, by a modification reaction of an isocyanate monomer using a metal catalyst. For example, the curing agent is produced by the following method. First, 1,3-xylylene diisocyanate and isobutyl alcohol are subjected to a urethane reaction. Next, bismuth octylate is added to the reaction solution, and an allophanation reaction is carried out. This produces a curing agent consisting of an allophanate derivative of xylylene diisocyanate (see, for example, Patent Document 1 (Preparation Example 32)). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. WO2015 / 133496 Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, the allophanate derivatives mentioned above contain a metal catalyst, which makes them relatively highly reactive, resulting in the problem that the pot life is not sufficient after mixing the curing agent with the base resin.

[0006] The present invention is a two-component curing polyurethane composition having an excellent pot life. [Means for solving the problem]

[0007] The present invention [1] is a two-component curing polyurethane composition comprising a curing agent, a base component, and a reaction retarder, wherein the curing agent comprises a polyisocyanate component containing an allophanate derivative of xylylene diisocyanate and a metal catalyst, the base component comprises a polyol component, and the reaction retarder comprises a phosphate ester, and the ratio of the phosphate ester to 1 mol of metal in the metal catalyst is 4 mol or more and 50 mol or less.

[0008] The present invention [2] includes the two-component curing polyurethane composition according to the above [1], in which the metal catalyst is a bismuth-containing catalyst.

[0009] The present invention [3] comprises the two-component curing polyurethane composition according to the above [1] or [2], wherein the content of the isocyanurate derivative of xylylene diisocyanate in the curing agent is 5 mass% or less relative to the total amount of the allophanate derivative of xylylene diisocyanate and the isocyanurate derivative of xylylene diisocyanate.

[0010] The present invention [4] includes the two-component curing polyurethane composition according to any one of the above [1] to [3], wherein the molecular weight of the phosphate ester is 100 or more and 300 or less.

[0011] The present invention [5] includes the two-component curing polyurethane composition according to any one of the above [1] to [4], wherein the molecular weight of the phosphate ester is 100 or more and 160 or less.

[0012] The present invention [6] comprises the two-component curing polyurethane composition according to any one of the above [1] to [5], wherein the ratio of the phosphate ester per mole of the metal in the metal catalyst is 10 moles or more and 30 moles or less. [Effects of the Invention]

[0013] In the two-component curing polyurethane composition of the present invention, the curing agent contains an allophanate derivative of xylylene diisocyanate and a metal catalyst. The reaction retarder contains a phosphate ester. The ratio of the phosphate ester to the metal in the metal catalyst is adjusted to a predetermined amount. Therefore, the two-component curing polyurethane composition of the present invention has an excellent pot life. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a correlation diagram showing the relationship between the amount of reaction retarder (phosphate ester) added and pot life. [Figure 2] FIG. 2 is a correlation diagram showing the relationship between the molar ratio of the reaction retarder (phosphate ester) to the metal atoms in the catalyst and the pot life. DETAILED DESCRIPTION OF THE INVENTION

[0015] A two-component curing polyurethane composition is a resin composition (resin kit). The two-component curing polyurethane composition contains a curing agent and a base agent. The base agent and the curing agent are each prepared as independent packages. When using the two-component curing polyurethane composition, the base agent and the curing agent are blended to form a polyurethane resin.

[0016] More specifically, the two-component curing polyurethane composition contains a curing agent, a base resin, and a reaction retarder.

[0017] The curing agent contains a polyisocyanate component, which is a component containing free isocyanate groups, and an allophanate composition.

[0018] The allophanate composition contains an allophanate derivative of xylylene diisocyanate and a metal catalyst. More specifically, the allophanate composition contains the allophanate derivative of xylylene diisocyanate as a main component. The allophanate composition also contains a metal catalyst as a secondary component. The proportion of the main component is, for example, 90% by mass or more relative to the allophanate composition. The proportion of the secondary component is, for example, 10% by mass or less relative to the allophanate composition.

[0019] The allophanate derivative of xylylene diisocyanate contains one or more allophanate groups in the molecule. For example, the allophanate derivative of xylylene diisocyanate is an alcohol-modified product of xylylene diisocyanate. The allophanate composition can be prepared, for example, by the following method.

[0020] In this method, first, xylylene diisocyanate and alcohol are subjected to a urethane reaction to obtain a urethane compound of xylylene diisocyanate.

[0021] Examples of xylylene diisocyanate (XDI) include 1,2-xylylene diisocyanate (o-xylylene diisocyanate (o-XDI)), 1,3-xylylene diisocyanate (m-xylylene diisocyanate (m-XDI)), and 1,4-xylylene diisocyanate (p-xylylene diisocyanate (p-XDI)). These can be used alone or in combination of two or more. Preferred xylylene diisocyanates include 1,3-xylylene diisocyanate and 1,4-xylylene diisocyanate, and more preferably 1,3-xylylene diisocyanate.

[0022] Examples of alcohols include aliphatic alcohols and aromatic alcohols, and preferably aliphatic alcohols, including monohydric aliphatic alcohols and dihydric aliphatic alcohols.

[0023] Examples of monohydric aliphatic alcohols include linear monohydric aliphatic alcohols and branched monohydric aliphatic alcohols. Examples of linear monohydric aliphatic alcohols include linear monohydric aliphatic alcohols having 1 to 20 carbon atoms. Examples of linear monohydric aliphatic alcohols having 1 to 20 carbon atoms include methanol, ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol, n-undecanol, n-dodecanol (lauryl alcohol), n-tridecanol, n-tetradecanol, n-pentadecanol, n-hexadecanol, n-heptadecanol, n-octadecanol (stearyl alcohol), n-nonadecanol, and eicosanol. Examples of branched monohydric aliphatic alcohols include branched monohydric aliphatic alcohols having 3 to 20 carbon atoms. Examples of branched monohydric aliphatic alcohols having 3 to 20 carbon atoms include isopropanol, isobutanol (isobutyl alcohol), sec-butanol, tert-butanol, isopentanol, isohexanol, isoheptanol, isooctanol, 2-ethylhexanol, isononanol, isodecanol, 5-ethyl-2-nonanol, trimethylnonyl alcohol, 2-hexyldecanol, 3,9-diethyl-6-tridecanol, 2-isoheptylisoundecanol, and 2-octyldodecanol. These may be used alone or in combination of two or more.

[0024] Dihydric aliphatic alcohols include linear dihydric aliphatic alcohols, branched dihydric aliphatic alcohols, and alicyclic dihydric aliphatic alcohols. Examples of linear dihydric aliphatic alcohols include methanediol, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-dihydroxy-2-butene, diethylene glycol, triethylene glycol, and dipropylene glycol. Examples of branched dihydric aliphatic alcohols include 1,2-propanediol, 1,3-butanediol, 1,2-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 3,3-dimethylolheptane, and 2,6-dimethyl-1-octene-3,8-diol. Examples of alicyclic dihydric aliphatic alcohols include cyclohexanedimethanol, cyclohexanediol, and hydrogenated bisphenol A. These can be used alone or in combination of two or more kinds.

[0025] The alcohol may also have a functional group other than a hydroxyl group. Examples of the functional group include an ester group, an ether group, a cyclohexane ring, and an aromatic ring. Examples of such alcohols include ether group-containing alcohols and ester group-containing alcohols. Examples of the ether group-containing alcohols include addition polymers of aliphatic alcohols and alkylene oxides. Examples of the ester group-containing alcohols include addition polymers of aliphatic alcohols and lactones.

[0026] These alcohols can be used alone or in combination of two or more.

[0027] The alcohol is preferably an aliphatic alcohol. The aliphatic alcohol is preferably an aliphatic alcohol having 1 to 20 carbon atoms, more preferably an aliphatic alcohol having 2 to 20 carbon atoms, even more preferably an aliphatic alcohol having 2 to 8 carbon atoms, and particularly preferably an aliphatic alcohol having 2 to 6 carbon atoms.

[0028] Furthermore, as the aliphatic alcohol, preferably, a monohydric aliphatic alcohol is used, more preferably, a branched monohydric aliphatic alcohol is used, even more preferably, a branched monohydric aliphatic alcohol having 3 to 6 carbon atoms is used, and particularly preferably, isobutyl alcohol is used.

[0029] The blending ratio of the alcohol and xylylene diisocyanate is adjusted so that there is an excess of isocyanate groups. The equivalent ratio (NCO / OH) of the isocyanate groups of the xylylene diisocyanate to the hydroxy groups of the alcohol is, for example, 2 or more, preferably 3 or more, more preferably 5 or more, and even more preferably 7 or more. The equivalent ratio (NCO / OH) of the isocyanate groups of the xylylene diisocyanate to the hydroxy groups of the alcohol is, for example, 1000 or less, preferably 100 or less, and more preferably 50 or less.

[0030] The blending ratio of the alcohol, based on mass, is, for example, 1.0 part by mass or more, preferably 2.0 parts by mass or more, more preferably 3.0 parts by mass or more, and more preferably 3.5 parts by mass or more, relative to 100 parts by mass of xylylene diisocyanate. The blending ratio of the alcohol is, for example, 50 parts by mass or less, preferably 30 parts by mass or less, and more preferably 20 parts by mass or less, relative to 100 parts by mass of xylylene diisocyanate.

[0031] In addition, in the urethanization reaction, other urethane raw materials are added in appropriate proportions as needed. Examples of other urethane raw materials include thiols, oximes, lactams, phenols, and β-diketones. These can be used alone or in combination of two or more. Preferably, other urethane raw materials are not added.

[0032] In addition, in the urethanization reaction, a urethanization catalyst is added in an appropriate ratio as needed. Examples of the urethanization catalyst include amines, organometallic compounds, and potassium salts. These can be used alone or in combination of two or more. Preferably, no urethanization catalyst is added. In other words, the urethanization reaction is preferably a non-catalyzed reaction.

[0033] The environmental conditions for the urethanization reaction are, for example, atmospheric pressure and an inert gas atmosphere, such as nitrogen gas and argon gas.

[0034] The reaction temperature in the urethanization reaction is, for example, 25° C. or higher, preferably 40° C. or higher, and more preferably 60° C. or higher. The reaction temperature is, for example, 100° C. or lower, preferably 90° C. or lower, and more preferably 80° C. or lower.

[0035] The reaction time in the urethanization reaction is, for example, 0.05 hours or more, preferably 0.2 hours or more, more preferably 1 hour or more, and even more preferably 3 hours or more, and for example, 10 hours or less, preferably 6 hours or less, and more preferably 4 hours or less.

[0036] Next, in this method, a metal catalyst is added to the reaction solution obtained by the urethanization reaction, and the reaction product of xylylene diisocyanate and alcohol is subjected to an allophanate-forming reaction.

[0037] The metal catalyst is an allophanate catalyst. When an amine catalyst is used instead of a metal catalyst, an allophanate derivative of xylylene diisocyanate is not sufficiently obtained. Therefore, a metal catalyst is used as the catalyst, and preferably, a metal catalyst is used alone.

[0038] In the metal catalyst, examples of the metal include lithium, sodium, potassium, magnesium, calcium, barium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, aluminum, gallium, indium, thallium, tin, lead, bismuth, and polonium. These can be used alone or in combination of two or more.

[0039] The metal is preferably bismuth or zinc, more preferably bismuth. In other words, the metal catalyst is preferably a bismuth-containing catalyst or a zinc-containing catalyst, more preferably a bismuth-containing catalyst. By using these, the by-production of an isocyanurate derivative of xylylene diisocyanate (described later) can be suppressed.

[0040] Examples of bismuth-containing catalysts include bismuth carboxylate. Examples of carboxylic acids include saturated aliphatic carboxylic acids, saturated monocyclic carboxylic acids, saturated polycyclic carboxylic acids, unsaturated aliphatic carboxylic acids, araliphatic carboxylic acids, and aromatic carboxylic acids. Examples of saturated aliphatic carboxylic acids include acetic acid, propionic acid, butyric acid, caproic acid, octylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, octylic acid, and 2-ethylhexanoic acid. Examples of saturated monocyclic carboxylic acids include cyclohexanecarboxylic acid and cyclopentanecarboxylic acid. Examples of saturated polycyclic carboxylic acids include bicyclo(4.4.0)decane-2-carboxylic acid. Examples of unsaturated aliphatic carboxylic acids include oleic acid, linoleic acid, linolenic acid, soybean oil fatty acid, and tall oil fatty acid. Examples of araliphatic carboxylic acids include diphenylacetic acid. Examples of aromatic carboxylic acids include benzoic acid and toluic acid. These can be used alone or in combination. Preferably, the carboxylic acid is a saturated aliphatic carboxylic acid.

[0041] The bismuth-containing catalyst can be used alone or in combination of two or more kinds. As the bismuth-containing catalyst, a bismuth carboxylate is preferably used. The use of a bismuth carboxylate can shorten the allophanate formation time.

[0042] In the bismuth-containing catalyst, the bismuth content (Bi concentration) is adjusted depending on the type of the bismuth-containing catalyst. For example, the Bi concentration is, for example, 10% by mass or more, preferably 13% by mass or more, and more preferably 15% by mass or more, based on the total amount of solids in the bismuth-containing catalyst. The Bi concentration is, for example, 50% by mass or less, preferably 40% by mass or less, and more preferably 35% by mass or less, based on the total amount of solids in the bismuth-containing catalyst.

[0043] The Bi concentration is the mass ratio of bismuth metal to the total amount of solids in the bismuth-containing catalyst, and can be measured by X-ray fluorescence analysis.

[0044] Examples of zinc-containing catalysts include zinc carboxylates, and examples of carboxylic acids include the above-mentioned carboxylic acids.

[0045] The zinc-containing catalyst may be used alone or in combination of two or more. A preferred example of the zinc-containing catalyst is zinc carboxylate.

[0046] In the zinc-containing catalyst, the zinc content (Zn concentration) is adjusted depending on the type of zinc-containing catalyst. For example, the Zn concentration is, for example, 10 mass% or more, preferably 13 mass% or more, more preferably 15 mass% or more, based on the total amount of solids in the zinc-containing catalyst. The Zn concentration is, for example, 50 mass% or less, preferably 40 mass% or less, more preferably 35 mass% or less, based on the total amount of solids in the zinc-containing catalyst.

[0047] The Zn concentration is the mass ratio of zinc metal to the total amount of solids in the zinc-containing catalyst, and can be measured by X-ray fluorescence analysis.

[0048] The metal catalyst may be 100% solid or may be in the form of a diluted solution, which is prepared, for example, by diluting the metal catalyst with a known organic solvent.

[0049] The addition ratio of the metal catalyst (solid content) relative to 100 parts by mass of xylylene diisocyanate is, for example, 0.001 parts by mass or more, preferably 0.005 parts by mass or more, more preferably 0.01 parts by mass or more. The addition ratio of the metal catalyst (solid content) relative to 100 parts by mass of xylylene diisocyanate is, for example, 0.3 parts by mass or less, preferably 0.2 parts by mass or less, more preferably 0.1 parts by mass or less.

[0050] The environmental conditions for the allophanatization reaction are, for example, atmospheric pressure and an inert gas atmosphere, such as nitrogen gas and argon gas.

[0051] The reaction temperature in the allophanatization reaction is, for example, 0° C. or higher, preferably 20° C. or higher, more preferably 40° C. or higher, even more preferably 60° C. or higher, and particularly preferably 70° C. or higher. The reaction temperature is, for example, 160° C. or lower, preferably 140° C. or lower, more preferably 120° C. or lower, and even more preferably 100° C. or lower.

[0052] The reaction time in the allophanatization reaction is, for example, 30 minutes or more, preferably 1 hour or more, more preferably 5 hours or more, and even more preferably 8 hours or more, and for example, 48 hours or less, more preferably 24 hours or less, and even more preferably 12 hours or less.

[0053] In the allophanate reaction, a catalyst deactivator is preferably added at any time to terminate the reaction. The catalyst deactivator is added, for example, when the ratio of urethane groups to allophanate groups in the reaction solution reaches a predetermined value. The urethane group / allophanate group ratio is measured as the IR ratio by, for example, infrared spectroscopy (IR method). For example, when the reaction is terminated, the IR ratio of urethane groups / allophanate groups is, for example, 0.3 or less, preferably 0.2 or less, and more preferably 0.1 or less.

[0054] Examples of catalyst deactivators include phosphoric acid, carboxylic acid, sulfonic acid, sulfonamide, and benzoyl chloride. Examples of carboxylic acids include monochloroacetic acid. Examples of sulfonic acids include dodecylbenzenesulfonic acid, paratoluenesulfonic acid, and orthotoluenesulfonic acid. Examples of sulfonamides include orthotoluenesulfonamide and paratoluenesulfonamide. These can be used alone or in combination of two or more. The blending ratio of the catalyst deactivator is not particularly limited and can be appropriately set depending on the purpose and application.

[0055] Then, by the above urethane-forming reaction and allophanate-forming reaction, an allophanate derivative of xylylene diisocyanate is obtained as the main product.

[0056] In the urethanization reaction and the allophanation reaction, a known organic solvent can be blended in an appropriate ratio, if necessary. In the urethanization reaction and the allophanation reaction, a known additive can be added, if necessary. An antioxidant is preferably used as the additive. The proportion of the additive added is appropriately determined depending on the purpose and application. The timing of adding the additive is not particularly limited. For example, the additive may be added to xylylene diisocyanate before the urethanization reaction. The additive may be added to the reaction liquid during the urethanization reaction and / or the allophanation reaction. Furthermore, the additive may be added to the reaction liquid after the urethanization reaction and the allophanation reaction.

[0057] This provides an allophanate composition containing an allophanate derivative of xylylene diisocyanate and a metal catalyst.

[0058] Furthermore, in the above-described method, unreacted xylylene diisocyanate can be removed by a known method from the reaction solution after the allophanate formation reaction. Furthermore, the catalyst, solvent, and / or catalyst deactivator can be removed by a known method from the reaction solution after the allophanate formation reaction. This allows the allophanate derivative of xylylene diisocyanate to be purified. However, even after purification, the metal catalyst inevitably remains in the allophanate composition.

[0059] The content of the metal catalyst in the allophanate composition is appropriately set depending on the purpose and application. For example, the metal atoms in the metal catalyst are, relative to the total amount of the allophanate composition, for example, 10 ppm or more, preferably 20 ppm or more, more preferably 50 ppm or more, and for example, 200 ppm or less, preferably 150 ppm or less, more preferably 100 ppm or less. The content of the metal atoms can be determined by X-ray fluorescence analysis (XRF analysis) in accordance with the examples described later (the same applies hereinafter).

[0060] Furthermore, in the above-mentioned method, depending on the type of metal catalyst and the reaction conditions, other xylylene diisocyanate derivatives may be obtained as by-products along with the allophanate derivative of xylylene diisocyanate.

[0061] The other xylylene diisocyanate derivatives are derivatives other than allophanate derivatives of xylylene diisocyanate. Examples of the other xylylene diisocyanate derivatives include isocyanurate derivatives of xylylene diisocyanate and uretdione dimers of xylylene diisocyanate, and preferably the isocyanurate derivatives of xylylene diisocyanate.

[0062] The content of the isocyanurate derivative of xylylene diisocyanate relative to the total amount (total mass) of the allophanate derivative of xylylene diisocyanate and the isocyanurate derivative of xylylene diisocyanate is, for example, 10 mass% or less, preferably 8 mass% or less, more preferably 5 mass% or less, even more preferably 3 mass% or less, still more preferably 1 mass% or less, and particularly preferably 0 mass%.

[0063] Furthermore, the content of the allophanate derivative of xylylene diisocyanate relative to the total amount (total mass) of the allophanate derivative of xylylene diisocyanate and the isocyanurate derivative of xylylene diisocyanate is, for example, 90 mass% or more, preferably 92 mass% or more, more preferably 95 mass% or more, even more preferably 97 mass% or more, still more preferably 99 mass% or more, and particularly preferably 100 mass%.

[0064] When the ratio of the allophanate derivative of xylylene diisocyanate to the isocyanurate derivative of xylylene diisocyanate is within the above range, a particularly excellent pot life can be obtained.

[0065] Note that the allophanate derivative of xylylene diisocyanate refers to an allophanate dimolecular body. Furthermore, the isocyanurate derivative of xylylene diisocyanate refers to an isocyanurate trimer. Furthermore, the ratio of the allophanate derivative of xylylene diisocyanate to the isocyanurate derivative of xylylene diisocyanate is the ratio of the allophanate dimolecular body in the allophanate composition to the isocyanurate trimer in the allophanate composition.

[0066] The ratio of allophanate dimolecular units to isocyanurate trimolecular units can be measured by gel permeation chromatography in accordance with the examples described below.

[0067] The allophanate composition has an isocyanate group concentration (100% by mass of solids) of, for example, 10% by mass or more, preferably 15% by mass or more, and more preferably 16% by mass or more. The allophanate composition has an isocyanate group concentration (100% by mass of solids) of, for example, 45% by mass or less, preferably 40% by mass or less, and more preferably 35% by mass or less.

[0068] The allophanate composition has an isocyanate monomer concentration (concentration of unreacted xylylene diisocyanate) of, for example, 5% by mass or less, preferably 2% by mass or less, or more preferably 1% by mass or less.

[0069] The proportion of the allophanate derivative of xylylene diisocyanate relative to the total amount of the allophanate composition is, for example, 90 mass % or more, preferably 95 mass % or more, more preferably 98 mass % or more, and for example, 99.9 mass % or less.

[0070] The polyisocyanate component contains an allophanate composition, and preferably consists of an allophanate composition. That is, the polyisocyanate component may contain, for example, a polyisocyanate other than the allophanate composition (for example, a known polyisocyanate monomer, a known polyisocyanate derivative, etc.), but preferably consists of an allophanate composition.

[0071] The curing agent may contain a known organic solvent as needed. The solid content concentration of the curing agent is appropriately set depending on the purpose and application.

[0072] The base agent contains a polyol component, which is a component containing free hydroxyl groups.

[0073] The polyol component includes, for example, a high molecular weight polyol and a low molecular weight polyol.

[0074] The high-molecular-weight polyol is an organic compound having two or more hydroxyl groups in the molecule and a relatively high molecular weight. The number-average molecular weight of the high-molecular-weight polyol is, for example, 300 or more, preferably 400 or more, and more preferably 500 or more. The number-average molecular weight of the high-molecular-weight polyol is, for example, 5000 or less, preferably 3000 or less.

[0075] Examples of high molecular weight polyols include polyether polyols, polyester polyols, acid-modified polyester polyols, polycarbonate polyols, polyurethane polyols, epoxy polyols, vegetable oil polyols, polyolefin polyols, acrylic polyols, and vinyl monomer-modified polyols. These high molecular weight polyols can be used alone or in combination of two or more. Preferred high molecular weight polyols include polyether polyols, polyester polyols, acid-modified polyester polyols, polycarbonate polyols, and acrylic polyols.

[0076] In particular, preferred examples of the high molecular weight polyol in the coating material (described later) include polyether polyol, polyester polyol, polycarbonate polyol, and acrylic polyol, and preferred examples of the high molecular weight polyol in the adhesive (described later) include polyester polyol.

[0077] The low-molecular-weight polyol is an organic compound having two or more hydroxyl groups in the molecule and having a relatively low molecular weight. The molecular weight of the low-molecular-weight polyol is, for example, less than 300, preferably less than 400. The molecular weight of the low-molecular-weight polyol is, for example, 40 or more.

[0078] Examples of low-molecular-weight polyols include dihydric alcohols, trihydric alcohols, and tetrahydric or higher alcohols. Examples of dihydric alcohols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, and dipropylene glycol. Examples of trihydric alcohols include glycerin and trimethylolpropane. Examples of tetrahydric or higher alcohols include pentaerythritol and diglycerin. These low-molecular-weight polyols can be used alone or in combination.

[0079] These polyol components can be used alone or in combination of two or more kinds.

[0080] The polyol component preferably includes a high-molecular-weight polyol, and more preferably does not contain a low-molecular-weight polyol and is composed of a high-molecular-weight polyol.

[0081] The base agent may contain a known organic solvent as needed. The solid content concentration of the base agent is appropriately set depending on the purpose and application.

[0082] The proportion of the base agent in the two-component curing polyurethane composition is adjusted appropriately so that the equivalent ratio of the isocyanate groups in the curing agent to the hydroxyl groups in the base agent falls within the range described below.

[0083] The reaction retarder contains a phosphate ester. Preferably, the reaction retarder is made of a phosphate ester. Examples of the phosphate ester include orthophosphate ester.

[0084] Examples of orthophosphate esters include alkyl acid phosphates having an alkyl group containing 1 to 20 carbon atoms and alkoxy acid phosphates having an alkoxy group containing 1 to 20 carbon atoms. Examples of alkyl acid phosphates having an alkyl group containing 1 to 20 carbon atoms include methyl acid phosphate, ethyl acid phosphate, pentyl acid phosphate, butyl acid phosphate, hexyl acid phosphate, octyl acid phosphate, 2-ethylhexyl acid phosphate, and oleyl acid phosphate. Examples of alkoxy acid phosphates having an alkoxy group containing 1 to 20 carbon atoms include methoxy acid phosphate, ethoxy acid phosphate, pentoxy acid phosphate, butoxy acid phosphate, hexoxy acid phosphate, and octoxy acid phosphate. These can be used alone or in combination of two or more.

[0085] The molecular weight of the phosphate ester is, for example, 100 or more, preferably 105 or more, and more preferably 110 or more. The molecular weight of the phosphate ester is, for example, 500 or less, preferably 450 or less, more preferably 400 or less, even more preferably 300 or less, still more preferably 200 or less, and particularly preferably 160 or less.

[0086] If the molecular weight of the phosphate ester is within the above range, a particularly excellent pot life can be obtained.

[0087] The phosphate ester is preferably an orthophosphate ester, more preferably an alkyl acid phosphate having an alkyl group having 1 to 20 carbon atoms, even more preferably an alkyl acid phosphate having an alkyl group having 1 to 10 carbon atoms, still more preferably an alkyl acid phosphate having an alkyl group having 1 to 3 carbon atoms, and particularly preferably methyl acid phosphate.

[0088] The reaction retarder may further include other reaction retarders. The other reaction retarders are reaction retarders other than phosphate esters. Examples of other reaction retarders include gallic acid, gallic acid alkyl esters, tannic acid, pyrogallol, 5-alkyl-pyrogallol, 2,5-dimethyl-4-hydroxy-furanone, 2-hydroxyethyl-4-hydroxy-furanone, 2-hydroxyethyl-1,4-naphthoquinone, maltol, ethyl maltol, kojic acid, α-tropolone, 5-alkyl-tropolone, 5-hydroxyalkyl-tropolone, β-thujaplicin, flavonol, morin, and fisetin. These may be used alone or in combination.

[0089] The proportion of the other reaction retarder is appropriately selected within a range that does not impair the excellent effects of the present invention.

[0090] In the reaction retarder, the proportion of the phosphate ester relative to the total amount of the reaction retarder is, for example, 50 mass% or more, preferably 55 mass% or more, more preferably 80 mass% or more, even more preferably 90 mass% or more, and particularly preferably 100 mass%. That is, the reaction retarder preferably consists of a phosphate ester.

[0091] In a two-component curing polyurethane composition, the timing of adding the reaction retarder is not particularly limited. For example, the reaction retarder may be premixed with the base agent and / or curing agent. Alternatively, the reaction retarder may be prepared separately from the base agent and curing agent and added when the base agent and curing agent are mixed (described below). Furthermore, the reaction retarder may be prepared separately from the base agent and curing agent and added to the mixture of the base agent and curing agent.

[0092] From the viewpoint of extending the usable time, the reaction retarder is preferably not mixed with the curing agent but is mixed in advance with the base agent. Alternatively, the reaction retarder is preferably prepared separately from the base agent and the curing agent and added when the base agent and the curing agent are mixed (described later). More preferably, the reaction retarder is mixed in advance with the base agent.

[0093] The proportion of the reaction retarder is adjusted, for example, as the ratio of the metal catalyst to the metal in the mixture of the curing agent, base agent and reaction retarder.

[0094] More specifically, the ratio of the phosphate ester to 1 mole of the metal in the metal catalyst contained in the curing agent is 4 moles or more, preferably 5 moles or more, more preferably 8 moles or more, even more preferably 10 moles or more, even more preferably 15 moles or more, and particularly preferably 20 moles or more. Also, the ratio of the phosphate ester to 1 mole of the metal in the metal catalyst contained in the curing agent is 50 moles or less, preferably 45 moles or less, more preferably 40 moles or less, even more preferably 35 moles or less, and particularly preferably 30 moles or less.

[0095] Furthermore, the two-component curing polyurethane composition may further contain other additives as needed. The other additives are additives other than reaction retarders. Examples of the other additives include plasticizers, antiblocking agents, heat stabilizers, light stabilizers, antioxidants, release agents, pigments, dyes, lubricants, fillers, and hydrolysis inhibitors. The proportions of the other additives added are determined appropriately depending on the purpose and application. The timing of adding the other additives is determined appropriately.

[0096] The two-component curing polyurethane composition is suitable for use as a paint, an adhesive, etc. Examples of the paint include a two-component curing paint, and examples of the adhesive include a two-component curing adhesive.

[0097] More specifically, first, a first liquid (liquid A) containing a base resin and a reaction retarder and a second liquid (liquid B) containing a curing agent are prepared, and then, just before use, the first and second liquids are mixed to prepare a two-liquid curing polyurethane mixture (paint, adhesive).

[0098] Alternatively, for example, a first liquid (liquid A) containing the base agent, a second liquid (liquid B) containing the curing agent, and a third liquid (liquid C) containing the reaction retarder may be prepared. In this case, the first, second, and third liquids can be mixed together immediately before use to prepare a two-liquid curing polyurethane mixture (paint, adhesive).

[0099] Alternatively, for example, a first liquid (liquid A) containing the base agent, a second liquid (liquid B) containing the curing agent, and a third liquid (liquid C) containing the reaction retarder can be prepared, and the first and second liquids can be mixed immediately before use. Then, the third liquid can be added to and mixed with the resulting mixture to prepare a two-liquid curing polyurethane mixture (paint, adhesive).

[0100] Preferably, a first liquid (liquid A) containing the base agent and the reaction retarder and a second liquid (liquid B) containing the curing agent are prepared, and the first and second liquids are mixed together immediately before use to prepare a two-liquid curing polyurethane mixture (paint, adhesive).

[0101] In other words, the two-component curing polyurethane composition is preferably a two-component polyurethane composition consisting of a first component (component A) containing a base resin and a reaction retarder, and a second component (component B) containing a curing agent but not a reaction retarder.

[0102] The blending ratio of the first liquid to the second liquid is, for example, a ratio such that the equivalent ratio (NCO / OH) of the isocyanate groups in the curing agent (polyisocyanate component) to the hydroxyl groups in the main agent (polyol component) is, for example, 0.5 or more, preferably 0.8 or more, more preferably 0.9 or more, and for example, 2 or less, preferably 1.5 or less, more preferably 1.2 or less.

[0103] If necessary, a known organic solvent is added to adjust the viscosity of the two-component curing polyurethane mixture. The amount of organic solvent added is not particularly limited and is adjusted appropriately. The organic solvent may be added to the first component, the second component, or the third component, or may be added during mixing of these components, or may even be added to the two-component curing polyurethane mixture.

[0104] The two-component curing polyurethane mixture is then applied to the adherend by any method. Examples of application methods include spray coating, air spray coating, brush coating, dipping, roll coating, flow coating, dry lamination, wet lamination, and direct coating. The adherend is not particularly limited, and examples thereof include various building materials and various laminate films.

[0105] The two-component curing polyurethane resin (mixture) is then dried and cured to obtain a polyurethane resin, which can be used in the form of, for example, a cured coating film or an adhesive layer.

[0106] In this two-component curing polyurethane composition, the curing agent contains an allophanate derivative of xylylene diisocyanate and a metal catalyst. The reaction retarder contains a phosphate ester. The ratio of the phosphate ester to the metal in the metal catalyst is adjusted to a predetermined value. Therefore, the two-component curing polyurethane composition has an excellent pot life.

[0107] Therefore, the two-component curing polyurethane composition is suitable for use in various industrial fields, for example, as a coating material or adhesive. [Example]

[0108] Next, the present invention will be described based on synthesis examples, examples, and comparative examples, but the present invention is not limited to the following examples. Note that "parts" and "%" are by mass unless otherwise specified. Furthermore, specific numerical values ​​such as blending ratios (content ratios), physical property values, and parameters used in the following description can be substituted with the corresponding upper limit values ​​(numeric values ​​defined as "equal to or less than") or lower limit values ​​(numeric values ​​defined as "equal to or more than" or "exceeding") of the blending ratios (content ratios), physical property values, parameters, etc. described in the above "Modes for Carrying Out the Invention."

[0109] Synthesis Example 1 (Curing agent A: Bi 60 ppm) A 1-liter four-neck flask equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet tube was charged with 104.1 parts by mass of 1,3-xylylene diisocyanate (m-XDI, manufactured by Mitsui Chemicals, Inc.), 11.7 parts by mass of isobutyl alcohol (equivalent ratio NCO / OH=7), 0.06 parts by mass of tris(2-ethylhexyl)phosphite (antioxidant), and 0.06 parts by mass of pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] (antioxidant) under a nitrogen atmosphere, and a urethanization reaction was carried out at 75°C for 3.5 hours. This produced a urethanized product.

[0110] Next, 0.01 parts by mass of bismuth octylate (trade name XK-628, manufactured by Kusumoto Chemicals Co., Ltd., bismuth content 31% by mass) was added as a metal catalyst to the reaction solution containing the urethane compound, and the allophanation reaction was carried out at 90°C for 11 hours, and it was confirmed that the conversion of urethane bonds to allophanate bonds was almost complete. The IR ratio (urethane groups / allophanate groups) at this time was 0.1 or less. Thereafter, 0.06 parts by mass of orthotoluenesulfonamide (reaction terminator) was added to the reaction solution to terminate the allophanation reaction.

[0111] The IR ratio (urethane group / allophanate group) was measured under the following conditions: the sample was measured using FT / IR-4100 manufactured by JASCO Corporation. -1 The urethane group peak near 3270 cm -1 The heights of the adjacent allophanate group peaks were calculated, and the peak ratio was taken as the IR ratio (urethane group / allophanate group).

[0112] Thereafter, unreacted isobutyl alcohol and 1,3-xylylene diisocyanate were removed from the reaction solution using a thin-film distillation apparatus (vacuum degree: 0.05 kPa, temperature: 150°C), yielding an allophanate composition containing an allophanate derivative of xylylene diisocyanate and a metal catalyst. The bismuth concentration in the allophanate composition was 60 ppm. The bismuth concentration was measured using a benchtop XRF analyzer, Epsilon 4, manufactured by Spectris. A calibration curve was prepared using a standard bismuth solution as described in JIS M 8230 (1994) (the same applies below).

[0113] The amount of the isocyanurate derivative in the allophanate composition was 0%. The amount of the isocyanurate derivative was measured by the following method.

[0114] That is, the sample was subjected to gel permeation chromatography (GPC) measurement, and the area ratio of the area of ​​each peak in the obtained chromatogram (chart) to the area of ​​all peaks was calculated.

[0115] The area ratio of the peak having a peak top in the range of 400 to 500 in terms of polystyrene molecular weight (Mn400-500 area ratio) was taken as the content of the allophanate derivative of xylylene diisocyanate.

[0116] Furthermore, the area ratio of the peak having a peak top in the range of 400 to 600 in terms of polystyrene molecular weight (Mn500-600 area ratio) was taken as the content of the isocyanurate derivative.

[0117] In addition, the area ratio of the peak having a peak top in the range of polystyrene-equivalent molecular weight of 150 to 250 (Mn150-350 area ratio) was taken as the content ratio of the xylylene diisocyanate monomer (the same applies hereinafter). The obtained allophanate composition is referred to as Curing Agent A.

[0118] Synthesis Example 2 (Hardening agent B: Bi 35 ppm) As a metal catalyst, 0.01 parts by mass of bismuth octylate (product name Neostan U-600, manufactured by Nitto Kasei, bismuth content 18% by mass) was used. An allophanate composition was obtained using the same method as in Synthesis Example 1. The bismuth concentration in the allophanate composition was 35 ppm. The amount of isocyanurate derivative in the allophanate composition was 0%. The obtained allophanate composition is referred to as Curing Agent B.

[0119] Synthesis Example 3 (Curing agent C: Zn 130 ppm) As the metal catalyst, 0.034 parts by mass of zinc 2-ethylhexanoate was used. Otherwise, an allophanate composition was obtained in the same manner as in Synthesis Example 1. The zinc concentration in the allophanate composition was 130 The zinc concentration was measured using a benchtop XRF device Epsilon 4 manufactured by Spectris. A calibration curve was prepared using a standard zinc solution described in JIS M 8228 (1997) (the same applies hereinafter). The amount of the isocyanurate derivative in the allophanate composition was 7%. The obtained allophanate composition is referred to as Curing Agent C.

[0120] Synthesis Example 4 (Amine-catalyzed reaction) A 1-liter four-neck flask equipped with a stirrer, a thermometer, a condenser, and a nitrogen gas inlet tube was charged with 104.1 parts by mass of 1,3-xylylene diisocyanate (manufactured by Mitsui Chemicals, Inc., m-XDI), 11.7 parts by mass of isobutyl alcohol, and Tris 0.06 part by mass of (2-ethylhexyl)phosphite and 0.06 part by mass of pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] were added and subjected to a urethane reaction at 75° C. for 3.5 hours, thereby obtaining a urethane reaction liquid.

[0121] Next, 0.12 parts by mass of a 37% methanol solution of tetrabutylammonium hydroxide (TBAOH) was added to the reaction liquid containing the urethane compound. As a result, the isocyanurate reaction proceeded preferentially, and no allophanate reaction liquid was obtained.

[0122] Synthesis Example 5 (Curing Agent D) A 1-liter four-neck flask equipped with a stirrer, a thermometer, a condenser, and a nitrogen gas inlet tube was charged with 102.9 parts by mass of hexamethylene diisocyanate (manufactured by Tosoh Corporation, HDI), 13.0 parts by mass of isobutyl alcohol, and Tris 0.06 part by mass of (2-ethylhexyl)phosphite and 0.06 part by mass of pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] were charged, and a urethane reaction was carried out at 75° C. for 3.5 hours.

[0123] Next, 0.01 parts by mass of bismuth octylate XK-628 (catalyst) was added to the reaction solution, and an allophanation reaction was carried out at 90°C for 11 hours. After confirming that the conversion of urethane bonds to allophanate bonds was almost complete (the IR ratio of urethane groups / allophanate groups was 0.1 or less), 0.06 parts by mass of orthotoluenesulfonamide was added to terminate the allophanation reaction.

[0124] The unreacted isobutyl alcohol and hexamethylene diisocyanate were removed from the resulting reaction solution using a thin-film distillation apparatus (vacuum degree: 0.05 kPa, temperature: 130°C) to obtain an allophanate derivative of hexamethylene diisocyanate. This allophanate derivative (HDI allophanate) is referred to as Curing Agent D. The bismuth concentration of Curing Agent D was measured and found to be 60 ppm. The amount of isocyanurate derivative in Curing Agent D was 0%.

[0125] Synthesis Example 6 (Curing Agent E) A 1-liter four-neck flask equipped with a stirrer, a thermometer, a condenser, and a nitrogen gas inlet tube was charged with 106.8 parts by mass of bis(4-isocyanatophenyl)methane (Cosmonate PH, manufactured by Mitsui Chemicals SKC Polyurethanes), 9.0 parts by mass of isobutyl alcohol, and Tris 0.06 part by mass of (2-ethylhexyl)phosphite and 0.06 part by mass of pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] were charged, and a urethane reaction was carried out at 75° C. for 3.5 hours.

[0126] Next, 0.01 parts by mass of bismuth octylate XK-628 (catalyst) was added to the reaction solution, and an allophanation reaction was carried out at 90°C for 11 hours. After confirming that the conversion of urethane bonds to allophanate bonds was almost complete (the IR ratio of urethane groups / allophanate groups was 0.1 or less), 0.06 parts by mass of orthotoluenesulfonamide was added to terminate the allophanation reaction.

[0127] The unreacted isobutyl alcohol and bis(4-isocyanatophenyl)methane were removed from the resulting reaction solution using a thin-film distillation apparatus (vacuum degree: 0.05 kPa, temperature: 150°C) to obtain an allophanate derivative of bis(4-isocyanatophenyl)methane. This allophanate derivative (MDI allophanate) is referred to as Curing Agent E.

[0128] The bismuth concentration of curing agent E was measured and found to be 60 ppm. The amount of isocyanurate derivative in curing agent E was 0%.

[0129] Examples 1 to 15 and Comparative Examples 1 to 12 Two-component curing polyurethane composition According to the formulations shown in Tables 1 to 5, an acrylic polyol (trade name: Olester Q182, hydroxyl value 42 mgKOH / g), a reaction retarder, and a solvent (butyl acetate / PMA / ethyl acetate = 1 / 1 / 1 (mass ratio)) were mixed for 10 minutes. This produced a first liquid (liquid A) containing the main agent (polyol component) and the reaction retarder. Meanwhile, according to the formulations shown in Tables 1 to 5, a second liquid (liquid B) containing a curing agent was produced. In this way, a two-liquid curing polyurethane composition (resin kit) was obtained.

[0130] Polyurethane resin A substrate having a base coat layer formed thereon was prepared, and a clear coat layer was formed on the base coat layer using the above two-component curing polyurethane composition (resin kit).

[0131] More specifically, polyisocyanate (trade name: Takenate D-170N, isocyanate group content 20%) and acrylic polyol (trade name: Olestar QB1528T, hydroxyl value 120 mgKOH / g) were mixed in such a ratio that the equivalent ratio (NCO / OH) of the isocyanate groups in the polyisocyanate to the hydroxyl groups in the polyol was 1.0. Furthermore, butyl acetate was added to the resulting mixture so that the viscosity became 30-50 mPa·s, and the mixture was stirred.

[0132] Next, this mixture was sprayed onto standard test plates (types: electrogalvanized steel plate, tin plate, and glass plate) (hereinafter referred to as test plates) conforming to JIS G 3313 (2017) and JIS K 5600-1-4 (1999) to a film thickness of approximately 15 μm, and then dried at 80°C for 5 minutes. This produced a substrate with a base coat layer formed thereon.

[0133] Thereafter, a polyurethane resin was formed as a clear coat layer. More specifically, an acrylic polyol (trade name: Olester Q182, hydroxyl value 42 mgKOH / g), a reaction retarder, and a solvent (butyl acetate / PMA / ethyl acetate = 1 / 1 / 1 (mass ratio)) were mixed for 10 minutes according to the formulations shown in Tables 1 to 5. Next, a curing agent was added to the resulting mixture, and the mixture was mixed for 10 minutes. This resulted in a clear coat liquid. The resulting clear coat liquid was then spray-coated onto the base coat layer to a film thickness of approximately 35 μm, and dried at 80°C for 30 minutes. The dried coating was then left to stand for 7 days in a room at 23°C and a relative humidity of 55%. This resulted in a polyurethane resin as a clear coat layer.

[0134] evaluation (1) Pot life The pot life of the clear coating liquid was evaluated by the following method. That is, the pot life was defined as the time from the time when Liquid A and Liquid B were mixed until the coating liquid completely lost its fluidity at 25°C. When Curing Agent C was used (Comparative Example 9 and Example 15), the temperature condition was changed to 50°C.

[0135] The relationship between the amount of reaction retarder (phosphate ester) added and the pot life is shown in Figure 1. Also, the relationship between the molar ratio of reaction retarder (phosphate ester) to metal atoms in the catalyst and the pot life is shown in Figure 2.

[0136] 1 and 2, it was found that there is a relatively strong correlation between the molar ratio of the reaction retarder (phosphate ester) to the metal atoms in the catalyst and the pot life. It was also found that there is a relatively weak correlation between the amount of the reaction retarder (phosphate ester) added and the pot life. In other words, it was confirmed that the pot life depends on the molar ratio of the reaction retarder (phosphate ester) to the metal atoms in the catalyst.

[0137] (2) Chemical resistance Gauze was soaked in ethanol and moved back and forth over the surface of the clear coat layer (polyurethane resin) with a 2000g load applied. The number of times it was moved back and forth until the clear coat layer (polyurethane resin) peeled off or broke was used to evaluate chemical resistance.

[0138] [Table 1]

[0139] [Table 2]

[0140] [Table 3]

[0141] [Table 4]

[0142] [Table 5]

Claims

1. A two-component curing polyurethane composition comprising a curing agent and a base component, The two-component curing polyurethane composition further contains a reaction retarder, the curing agent contains a polyisocyanate component containing an allophanate derivative of xylylene diisocyanate and a metal catalyst; the metal catalyst is an allophanatization catalyst deactivated by a catalyst deactivator; The base agent contains a polyol component, The reaction retarder contains a phosphate ester, The phosphate ester is an alkyl acid phosphate having an alkyl group having 1 to 20 carbon atoms, a two-component curing polyurethane composition, wherein the ratio of the phosphate ester to 1 mole of the metal in the metal catalyst is 4 moles or more and 50 moles or less.

2. The two-component curing polyurethane composition according to claim 1 , wherein the metal catalyst is a bismuth-containing catalyst.

3. In the curing agent, 3. The two-component curing polyurethane composition according to claim 1, wherein a content of the isocyanurate derivative of xylylene diisocyanate is 5% by mass or less relative to the total amount of the allophanate derivative of xylylene diisocyanate and the isocyanurate derivative of xylylene diisocyanate.

4. The two-component curing polyurethane composition according to any one of claims 1 to 3, wherein the molecular weight of the phosphate ester is 100 or more and 300 or less.

5. The two-component curing polyurethane composition according to any one of claims 1 to 4, wherein the phosphate ester has a molecular weight of 100 or more and 160 or less.

6. 6. The two-component curing polyurethane composition according to claim 1, wherein a ratio of the phosphate ester relative to 1 mole of the metal in the metal catalyst is 10 moles or more and 30 moles or less.

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