Blocked polyisocyanate compositions, resin compositions, resin films, and laminates

Abstract

To provide a blocked polyisocyanate composition that offers superior storage stability when stored at high temperatures or low temperature, exhibits superior storage stability when made into a resin composition containing a polyhydric hydroxy compound, and demonstrates superior curability at low temperatures.SOLUTION: A blocked polyisocyanate composition contains blocked polyisocyanate. The blocked polyisocyanate is derived from polyisocyanate, and a blocker containing malonate diester. The malonate diester includes primary, secondary and tertiary alkyl groups.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a block polyisocyanate composition, a resin composition, a resin film, and a laminate. [Background technology]

[0002] Polyurethane resin coatings have traditionally been known to possess excellent abrasion resistance, chemical resistance, and stain resistance. In particular, polyurethane resin coatings using polyisocyanates obtained from aliphatic or alicyclic diisocyanates exhibit even greater weather resistance, and demand for them is on the rise.

[0003] However, conventional polyurethane resin paints consist of two components, polyol and polyisocyanate, which requires the separate storage of the polyol and polyisocyanate and the mixing of the two during application. Furthermore, once the two are mixed, the paint gels quickly and becomes unusable, posing a significant challenge.

[0004] Polyurethane resin paints have these challenges, making them difficult to use in line painting applications such as automotive painting or electrocoating. Furthermore, because isocyanates readily react with water, they cannot be used in water-based paints such as electrodeposition paints. Additionally, using paints containing isocyanates requires thorough cleaning of the painting machine and tank after each use, resulting in reduced work efficiency.

[0005] To address the aforementioned challenges, it has been proposed to use blocked polyisocyanates, in which all active isocyanate groups are blocked with a blocking agent. These blocked polyisocyanates do not react with polyols at room temperature. However, heating causes the blocking agent to dissociate, regenerating the active isocyanate groups, which then react with the polyol to cause a crosslinking reaction, thus overcoming the aforementioned challenges. Consequently, numerous blocking agents have been investigated, with phenol and methyl ethyl ketoxime being typical examples.

[0006] However, when using blocked polyisocyanates with these blocking agents, a high curing temperature of 140°C or higher is generally required. This high curing temperature is not only energy-intensive but also necessitates heat resistance in the substrate, limiting its applications.

[0007] On the other hand, research is being conducted on low-temperature curing type block polyisocyanates using active methylene compounds such as acetoacetate esters and malonic acid esters. For example, Patent Documents 1 and 2 propose block polyisocyanate compositions that cure at 90°C. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2002-322238 [Patent Document 2] Japanese Patent Publication No. 2006-335954 [Overview of the project] [Problems that the invention aims to solve]

[0009] In recent years, there has been a strong demand for block polyisocyanate compositions that cure at temperatures below 90°C, both from the perspective of protecting the global environment and for applications in plastics with low heat resistance.

[0010] The present invention has been made in view of the above circumstances, and aims to provide a block polyisocyanate composition that exhibits good storage stability when stored at high or low temperatures, has excellent storage stability when used as a resin composition containing a polyvalent hydroxy compound, and further exhibits excellent curability at low temperatures, a resin composition using the block polyisocyanate composition, a resin film, and a laminate.

[0011] In this specification, "excellent storage stability when stored at high temperatures" means that no change is observed when the blocked polyisocyanate composition is stored at 50-60°C for one week, according to the evaluation method described in the examples. In this specification, "excellent storage stability when stored at low temperatures" means that the blocked polyisocyanate composition remains liquid when stored at -10°C for one week, according to the evaluation method described in the examples. In this specification, storage stability is evaluated by the rate of change in viscosity before and after storage when a resin composition containing a blocked polyisocyanate composition and a polyvalent hydroxy compound is stored at 40°C for 3 days, according to the evaluation method described in the examples. In this specification, "excellent curing properties at low temperatures" means curing at a temperature of 80 to 85°C. [Means for solving the problem]

[0012] In other words, the present invention includes the following embodiments. [1] A blocked polyisocyanate composition comprising a blocked polyisocyanate, wherein the blocked polyisocyanate is derived from a polyisocyanate and a blocking agent comprising a malonic acid diester, and the malonic acid diester is a malonic acid diester having primary, secondary and tertiary alkyl groups. [2] A blocked polyisocyanate composition comprising a blocked polyisocyanate, wherein the blocked polyisocyanate is derived from a polyisocyanate and one or more blocking agents, and the blocked polyisocyanate contains structural unit (I-1), structural unit (I-2), and structural unit (I-3) within its molecule. The aforementioned constituent unit (I-1) is R in the following general formula (I). 12 , R 13 , R 15 and R 16 However, the constituent unit is the hydrogen atom. The aforementioned constituent unit (I-2) is R in the following general formula (I). 11 , R 12 and R13 at least one of which is a hydrogen atom, and R 14 and R 15 is an alkyl group which may optionally contain one or more substituents selected from the group consisting of a hydroxy group and an amino group, and R 16 is a hydrogen atom. The structural unit (I-3) is a structural unit in which, in the following general formula (I), R 11 , R 12 and R 13 are each independently an alkyl group which may optionally contain one or more substituents selected from the group consisting of a hydroxy group and an amino group, and the total number of carbon atoms of R 11 , R 12 and R 13 is 3 or more and 20 or less.

Chemical Formula

[10] A laminate comprising one or more layers of the resin film described in [9] on a substrate, wherein the thickness of each layer constituting the laminate is 1 μm or more and 50 μm or less. [Effects of the Invention]

[0013] The block polyisocyanate composition of this embodiment provides good storage stability when stored at high or low temperatures, excellent storage stability when used as a resin composition containing a polyvalent hydroxy compound, and excellent curability at low temperatures. It also provides a block polyisocyanate composition, a resin composition using the block polyisocyanate composition, a resin film, and a laminate. Furthermore, the resin film of this embodiment has a high gel fraction. [Modes for carrying out the invention]

[0014] The following describes in detail embodiments for carrying out the present invention (hereinafter referred to as "this embodiment"). However, the present invention is not limited to the following embodiments. The present invention can be implemented with appropriate modifications within the scope of its gist.

[0015] In this specification, "polyol" means a compound having two or more hydroxyl groups (-OH). In this specification, "polyisocyanate" means a reaction product in which multiple monomer compounds having one or more isocyanate groups (-NCO) are bonded together.

[0016] In this specification, "constituent unit" means a structure in a polyisocyanate or blocked polyisocyanate that originates from a single monomer molecule. For example, a constituent unit derived from malonic acid diester refers to a structure in a blocked polyisocyanate that originates from a single molecule of malonic acid diester. A constituent unit may be a unit directly formed by a (co)polymerization reaction of monomers, or it may be a unit in which a part of the (co)polymer has been converted to another structure by processing.

[0017] <Blocked polyisocyanate composition> One aspect of the present invention is a blocked polyisocyanate composition comprising a blocked polyisocyanate. In this embodiment, the blocked polyisocyanate is derived from a polyisocyanate and a blocking agent containing a malonic acid diester. In this embodiment, the malonic acid diester is a malonic acid diester having primary, secondary, and tertiary alkyl groups.

[0018] One aspect of the present invention is a blocked polyisocyanate composition comprising a blocked polyisocyanate derived from a polyisocyanate and one or more blocking agents. The blocked polyisocyanate comprises a constituent unit (I).

[0019] [Constituent Unit (I)] The blocked polyisocyanate composition of this embodiment contains a constituent unit (I) represented by the following general formula (I) within the molecule.

[0020] [ka] (In general formula (I), R 11 , R 12 , R 13 , R 14 , R 15 and R 16 Each of these is an alkyl group that may independently contain a hydrogen atom or one or more substituents selected from the group consisting of a hydroxyl group and an amino group. (The wavy lines represent bonds.)

[0021] R 11 , R 12 , R 13 , R 14 , R 15 and R 16 The alkyl group in the compound preferably has 1 to 20 carbon atoms, more preferably 1 to 8 carbon atoms, even more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms.

[0022] Examples of alkyl groups without substituents include, for example, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, tert-butyl group, sec-butyl group, isobutyl group, n-pentyl group, isopentyl group, neopentyl group, tert-pentyl group, 1-methylbutyl group, n-hexyl group, 2-methylpentyl group, 3-methylpentyl group, 2,2-dimethylbutyl group, 2,3-dimethylbutyl group, n-heptyl group, 2-methylhexyl group, 3-methylhexyl group, 2,2-dimethylpentyl group, 2,3-dimethylpentyl group, 2,4-dimethylpentyl group, 3,3-dimethylpentyl group, 3-ethylpentyl group, 2,2,3-trimethylbutyl group, n-octyl group, isooctyl group, 2-ethylhexyl group, nonyl group, decyl group, and the like.

[0023] Also, R 11 , R 12 , R 13 , R 14 , R 15 and R 16 However, if it is an alkyl group with a substituent, the substituent is either a hydroxyl group or an amino group.

[0024] Examples of alkyl groups containing a hydroxyl group as a substituent include hydroxymethyl, hydroxyethyl, and hydroxypropyl groups.

[0025] Examples of alkyl groups containing an amino group as a substituent include aminomethyl, aminoethyl, aminopropyl, and aminobutyl groups.

[0026] Examples of alkyl groups containing a hydroxyl group and an amino group as substituents include hydroxyaminomethyl group, hydroxyaminoethyl group, and hydroxyaminopropyl group.

[0027] The constituent units represented by general formula (I) include constituent units (I-1), (I-2), and (I-3).

[0028] The constituent unit (I-1) is R 12 , R 13 , R 15 and R 16 However, it is a hydrogen atom. In other words, the constituent unit (I-1) is a malonic acid diester having only a primary alkyl group. The constituent unit (I-1) is R 11 and R 14 However, it is particularly preferable that both ester moieties of the malonic acid diester of the constituent unit (I-1) are ethyl groups, i.e., methyl groups.

[0029] The content of constituent unit (I-1) is preferably 1 mol% to 75 mol% of the total amount of constituent unit (I), more preferably 3 mol% to 50 mol%, and even more preferably 5 mol% to 30 mol%. When the content of constituent unit (I-1) is above the lower limit, the resin composition has excellent storage stability. When the content of constituent unit (I-1) is below the upper limit, the low-temperature curing properties are excellent.

[0030] The constituent unit (I-2) is R 11 , R 12 and R 13 One or more of them are hydrogen atoms, and R14 and R 15 R is an alkyl group which may contain one or more substituents selected from the group consisting of hydroxyl groups and amino groups, and 16 However, it is a hydrogen atom. That is, the constituent unit (I-2) is a malonic acid diester having only a secondary alkyl group, or a malonic acid diester having both a primary and a secondary alkyl group.

[0031] The content of constituent unit (I-2) is preferably 0.05 mol% to 10 mol% of the total amount of constituent unit (I), and more preferably 0.05 mol% to 8 mol%. A content of constituent unit (I-2) above the lower limit provides excellent storage stability of the block polyisocyanate composition at high or low temperatures. A content of constituent unit (I-2) below the upper limit provides excellent low-temperature curing properties.

[0032] It is preferable that the constituent unit (I-2) includes the constituent unit (I-2-1). The constituent unit (I-2-1) is R 12 and R 13 However, it is a hydrogen atom, and R 14 and R 15 R is an alkyl group which may contain one or more substituents selected from the group consisting of hydroxyl groups and amino groups, 16 However, the hydrogen atom is the constituent unit.

[0033] It is preferable that the constituent unit (I-2-1) constitutes 50% to 99% by mass of the total amount of constituent unit (I-2). Having the content of constituent unit (I-2-1) within the above range provides excellent low-temperature stability for the blocked polyisocyanate composition.

[0034] The constituent unit (I-3) is R 11 , R 12 and R 13 Each of these is an alkyl group which may contain one or more substituents selected from the group consisting of hydroxyl groups and amino groups, and R 11 , R 12 and R 13The total number of carbon atoms is between 3 and 20. In other words, the constituent unit (I-3) is a malonic acid diester that always has one tertiary alkyl group.

[0035] R of constituent unit (I-3) 11 , R 12 and R 13 The total number of carbon atoms is 3 to 20, more preferably 4 to 20, even more preferably 4 to 12, even more preferably 4 to 9, and even more preferably 4 to 6.

[0036] R 11 , R 12 and R 13 The total number of carbon atoms is greater than or equal to the above lower limit, resulting in excellent storage stability when used as a resin composition. 11 , R 12 and R 13 Because the total number of carbon atoms is below the above upper limit, it exhibits excellent low-temperature curing properties. Furthermore, from the viewpoint of solvent resistance when used as a coating film, R 11 , R 12 and R 13 It is more preferable that the total number of carbon atoms be 4.

[0037] The content of constituent unit (I-3) is preferably 20 mol% to 98 mol%, more preferably 30 mol% to 95 mol%, and particularly preferably 50 mol% to 90 mol% in the total amount of constituent unit (I). Having a constituent unit (I-3) content within the above range results in excellent low-temperature curing properties.

[0038] A constituent unit (I-3) includes, for example, a constituent unit (I-3-1). The constituent unit (I-3-1) is R 11 , R 12 , R 13 , R 14 , R 15 and R 16 However, all alkyl groups may contain substituents. The substituents on the constituent unit (I-3-1) are one or more selected from the group consisting of hydroxyl groups and amino groups.

[0039] From the viewpoint of the storage stability of the resin composition, the content ratio of the structural unit (I-3-1) relative to the total amount of the structural unit (I-3) is preferably 1 mol% or more and 50 mol% or less.

[0040] The content ratio (mol%) of each structural unit can be obtained, for example, by using a blocked polyisocyanate composition 1 1H-NMR and 13 13C-NMR to measure the composition ratio of the structural units (I-1), (I-2), and (I-3) relative to the structural unit represented by general formula (I), thereby calculating the molar ratio of each structural unit.

[0041] In the molecule of the blocked polyisocyanate contained in the blocked polyisocyanate composition of the present embodiment, the blocked polyisocyanate may be one in which at least a part of the isocyanate groups are blocked with a malonic acid diester having a secondary alkyl group or a malonic acid diester having a primary alkyl group, and a malonic acid diester having a tertiary alkyl group. Alternatively, it may be a mixture of a blocked polyisocyanate in which at least a part of the isocyanate groups in the polyisocyanate are blocked with a malonic acid diester having a secondary alkyl group, or a blocked polyisocyanate in which at least a part of the isocyanate groups in the polyisocyanate are blocked with a malonic acid diester having a primary alkyl group, and a blocked polyisocyanate in which at least a part of the isocyanate groups in the polyisocyanate are blocked with a malonic acid diester having a tertiary alkyl group.

[0042] [Other Functional Groups] The blocked polyisocyanate may have one or more functional groups selected from the group consisting of allophanate groups, uretdione groups, iminooxadiazinedione groups, isocyanurate groups, urethane groups and biuret groups. Among these, it is preferable to have an isocyanurate group because of excellent weather resistance.

[0043] The blocked polyisocyanate contained in the blocked polyisocyanate composition of this embodiment is derived from a polyisocyanate and at least one blocking agent.

[0044] [Polyisocyanate] Polyisocyanates used in the production of blocked polyisocyanates are reaction products obtained by reacting multiple monomer compounds having one or more isocyanate groups (-NCO) (hereinafter sometimes referred to as "isocyanate monomers").

[0045] The isocyanate monomer is preferably one having 4 to 30 carbon atoms. Specific examples of isocyanate monomers include the following. These isocyanate monomers may be used individually or in combination of two or more.

[0046] (1) Aromatic diisocyanates such as diphenylmethane-4,4'-diisocyanate (MDI), 1,5-naphthalene diisocyanate, tolylene diisocyanate (TDI), xylylene diisocyanate, and m-tetramethylxylylene diisocyanate (TMXDI).

[0047] (2) Aliphatic diisocyanates such as 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate (hereinafter sometimes referred to as "HDI"), 2,2,4-trimethyl-1,6-diisocyanatohexane, 2,4,4-trimethyl-1,6-hexamethylene diisocyanate, 2-methylpentane-1,5-diisocyanate (MPDI), and lysine diisocyanate (hereinafter sometimes referred to as "LDI").

[0048] (3) Alicyclic diisocyanates such as isophorone diisocyanate (hereinafter sometimes referred to as "IPDI"), 1,3-bis(diisocyanate methyl)cyclohexane, 4,4'-dicyclohexylmethane diisocyanate, diisocyanate norbornane, and di(isocyanate methyl)norbornane.

[0049] (4) Triisocyanates such as 4-isocyanate methyl-1,8-octamethylene diisocyanate (hereinafter sometimes referred to as "NTI"), 1,3,6-hexamethylene triisocyanate (hereinafter sometimes referred to as "HTI"), bis(2-isocyanatoethyl)2-isocyanatoglutarate (hereinafter sometimes referred to as "GTI"), and lysine triisocyanate (hereinafter sometimes referred to as "LTI").

[0050] As the isocyanate monomer used in the production of polyisocyanates, one or more diisocyanates selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates are preferred due to their excellent weather resistance. In addition, diisocyanate monomers other than the aliphatic and alicyclic diisocyanates mentioned above may also be used. Furthermore, HDI, PDI, or IPDI are more preferred as the isocyanate monomer due to their ease of industrial availability. Furthermore, HDI is even more preferred as the isocyanate monomer from the viewpoint of reducing the viscosity of the blocked polyisocyanate component.

[0051] Furthermore, as the isocyanate monomer used in the production of polyisocyanates, either aliphatic diisocyanates or alicyclic diisocyanates may be used alone or in combination, but it is preferable to use aliphatic diisocyanates and alicyclic diisocyanates in combination, and it is particularly preferable to use HDI and IPDI. By using aliphatic diisocyanates and alicyclic diisocyanates, the toughness and hardness of the coating film can be further improved.

[0052] In polyisocyanates, the mass ratio of constituent units derived from aliphatic diisocyanates to constituent units derived from alicyclic diisocyanates is preferably 50 / 50 or more and 95 / 5 or less, more preferably 60 / 40 or more and 92 / 8 or less, and even more preferably 65 / 35 or more and 90 / 10 or less.

[0053] By keeping the mass ratio of constituent units derived from aliphatic diisocyanates to constituent units derived from alicyclic diisocyanates above the lower limit, the decrease in flexibility when applied as a coating film can be more effectively suppressed. On the other hand, by keeping it below the upper limit, the hardness of the coating film can be further improved.

[0054] The mass ratio of constituent units derived from aliphatic diisocyanates to constituent units derived from alicyclic diisocyanates can be calculated, for example, using the following method. First, the mass of unreacted aliphatic diisocyanate and unreacted alicyclic diisocyanate is calculated from the mass of unreacted diisocyanate after the reaction and the concentrations of aliphatic diisocyanate and alicyclic diisocyanate in this unreacted diisocyanate obtained by gas chromatography. Next, the mass of unreacted aliphatic diisocyanate and unreacted alicyclic diisocyanate calculated above are subtracted from the mass of the charged aliphatic diisocyanate and alicyclic diisocyanate, respectively. The resulting difference is then taken as the mass of constituent units derived from aliphatic diisocyanate and the mass of constituent units derived from alicyclic diisocyanate, respectively. Next, by dividing the mass of the constituent units derived from aliphatic diisocyanates by the mass of the constituent units derived from alicyclic diisocyanates, the mass ratio of constituent units derived from aliphatic diisocyanates to those derived from alicyclic diisocyanates is obtained.

[0055] Polyisocyanates preferably have isocyanurate groups, and in addition to isocyanurate groups, they may have one or more functional groups selected from the group consisting of allophanate groups, uretdione groups, iminooxadiazinedione groups, isocyanurate groups, urethane groups, and biuret groups.

[0056] (Method for producing polyisocyanates) The method for producing polyisocyanate is described in detail below. Polyisocyanates can be obtained, for example, by simultaneously producing allophanate reactions to form allophanate groups, uretdione reactions to form uretdione groups, iminooxadiadindione reactions to form iminooxadiadindione groups, isocyanurate reactions to form isocyanurate groups, urethane reactions to form urethane groups, and biuret reactions to form biuret groups in the presence of an excess of isocyanate monomer, and then removing the unreacted isocyanate monomer after the reaction is complete. In other words, the polyisocyanate obtained by the above reaction is a reaction product in which multiple isocyanate monomers are bonded together and which has one or more groups selected from the group consisting of allophanate groups, uretdione groups, iminooxadiadindione groups, isocyanurate groups, urethane groups, and biuret groups. Alternatively, the above reactions may be carried out separately, and the resulting polyisocyanates may be mixed in a specific ratio. From the standpoint of ease of production, it is preferable to perform the above reaction in one step to obtain polyisocyanate; however, from the viewpoint of freely adjusting the molar ratio of each functional group, it is preferable to produce them separately and then mix them.

[0057] (1) Method for producing polyisocyanate containing allophanate group Allophanate group-containing polyisocyanates are obtained by adding an alcohol to an isocyanate monomer and using an allophanate reaction catalyst. The alcohol used to form the allophanate group is preferably an alcohol formed only from carbon, hydrogen, and oxygen.

[0058] The aforementioned alcohols are not limited to the following, but examples include monoalcohols and dialcohols. These alcohols may be used individually or in combination of two or more.

[0059] Examples of monoalcohols include methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, and nonanol. Examples of dialcohols include ethylene glycol, 1,3-butanediol, neopentyl glycol, and 2-ethylhexanediol. Among the alcohols, monoalcohols are preferred, and monoalcohols with a molecular weight of 200 or less are more preferred.

[0060] The allophanate reaction catalyst is not limited to the following, but examples include alkyl carboxylates of tin, lead, zinc, bismuth, zirconium, zirconyl, etc. Examples of alkyl carboxylates of tin (organotin compounds) include tin 2-ethylhexanoate and dibutyltin dilaurate.

[0061] Examples of alkyl carboxylates of lead (organic lead compounds) include lead 2-ethylhexanoate. Examples of zinc alkyl carboxylates (organozinc compounds) include zinc 2-ethylhexanoate. Examples of alkyl carboxylate salts of bismuth include bismuth 2-ethylhexanoate. Examples of alkyl carboxylate salts of zirconium include zirconium 2-ethylhexanoate. Examples of zirconyl alkyl carboxylates include zirconyl 2-ethylhexanoate. These catalysts can be used individually or in combination of two or more.

[0062] Furthermore, the isocyanurate reaction catalyst described later can also serve as an allophanate reaction catalyst. When the allophanate reaction is carried out using the isocyanurate reaction catalyst described later, isocyanurate group-containing polyisocyanates (hereinafter sometimes referred to as "isocyanurate-type polyisocyanates") are naturally produced.

[0063] In particular, it is economically preferable from a production standpoint to use the isocyanurate reaction catalyst described later as the allophanate reaction catalyst to carry out both the allophanate reaction and the isocyanurate reaction.

[0064] The amount of the allophanate reaction catalyst used is preferably 10 ppm or more by mass, more preferably 20 ppm or more by mass, even more preferably 40 ppm or more by mass, and particularly preferably 80 ppm or more by mass, relative to the mass of the charged isocyanate monomer.

[0065] The amount of the allophanate reaction catalyst used is preferably 1000 ppm or less by mass, more preferably 800 ppm or less by mass, even more preferably 600 ppm or less by mass, and particularly preferably 500 ppm or less by mass, relative to the mass of the charged isocyanate monomer.

[0066] In other words, the amount of allophanate reaction catalyst used is preferably 10 ppm to 1000 ppm by mass, more preferably 20 ppm to 800 ppm by mass, even more preferably 40 ppm to 600 ppm by mass, and particularly preferably 80 ppm to 500 ppm by mass, relative to the mass of the charged isocyanate monomer.

[0067] Furthermore, the allophanate reaction temperature is preferably 40°C or higher, more preferably 60°C or higher, even more preferably 80°C or higher, and particularly preferably 100°C or higher. Furthermore, the allophanate reaction temperature is preferably 180°C or lower, more preferably 160°C or lower, and even more preferably 140°C or lower.

[0068] In other words, the allophanate reaction temperature is preferably 40°C to 180°C, more preferably 60°C to 160°C, even more preferably 80°C to 140°C, and particularly preferably 100°C to 140°C.

[0069] By keeping the allophanate reaction temperature above the lower limit, the reaction rate can be further improved. By keeping the allophanate reaction temperature below the upper limit, discoloration of the polyisocyanate tends to be more effectively suppressed.

[0070] (2) Method for producing polyisocyanate containing urethione group When deriving polyisocyanates having a uretdione group from isocyanate monomers, they can be produced, for example, by increasing the volume of the isocyanate monomer using a uretdione reaction catalyst or by heat.

[0071] The catalyst for the uretdione reaction is not particularly limited, but examples include tertiary phosphines such as trialkylphosphines, tris(dialkylamino)phosphines, and cycloalkylphosphines, as well as Lewis acids. Examples of trialkylphosphines include tri-n-butylphosphine and tri-n-octylphosphine. Examples of tris(dialkylamino)phosphine include tris-(dimethylamino)phosphine. Examples of cycloalkylphosphines include cyclohexyl-di-n-hexylphosphine. Examples of Lewis acids include boron trifluoride and zinc acid chloride.

[0072] Many uretdione reaction catalysts can also simultaneously promote isocyanurate reactions. When using a uretdione reaction catalyst, it is preferable to stop the uretdione reaction by adding a catalyst deactivator such as phosphoric acid or methyl p-toluenesulfonate once the desired yield is achieved.

[0073] Furthermore, when obtaining a polyisocyanate having a uretdione group by heating one or more diisocyanates selected from the group consisting of the above aliphatic diisocyanates and the above alicyclic diisocyanates, without using a uretdione reaction catalyst, the heating temperature is preferably 120°C or higher, and more preferably 150°C to 170°C. The heating time is preferably 1 hour to 4 hours.

[0074] (3) Method for producing polyisocyanates containing iminooxadiazine groups When deriving imino-oxadiazinedione group-containing polyisocyanates from isocyanate monomers, an imino-oxadiazinedione reaction catalyst is typically used. Examples of imino-oxadiazinedione catalysts include those shown in 1) or 2) below.

[0075] 1) (Poly)hydrogen fluoride represented by the general formula M[Fn] or the general formula M[Fn(HF)m] (wherein m and n are integers satisfying the relationship m / n>0. M is an n-charged cation (mixture) or one or more radicals with a total charge of n).

[0076] 2) A compound comprising a compound represented by the general formula R1-CR'2-C(O)O- or R2=CR'-C(O)O- and a quaternary ammonium cation or a quaternary phosphonium cation (wherein R1 and R2 are each independently linear, branched, or cyclic saturated or unsaturated perfluoroalkyl groups having 1 to 30 carbon atoms. Each of the multiple R' groups is independently a hydrogen atom or an alkyl or aryl group having 1 to 20 carbon atoms, which may contain a heteroatom.)

[0077] 1) Examples of compounds ((poly)hydrogen fluoride) include, for example, tetramethylammonium fluoride hydrate and tetraethylammonium fluoride.

[0078] 2) Specifically, examples of compounds include 3,3,3-trifluorocarboxylic acid, 4,4,4,3,3-pentafluorobutanoic acid, 5,5,5,4,4,3,3-heptafluoropentanoic acid, and 3,3-difluoropropane-2-enoic acid.

[0079] Among these, as the catalyst for the imino-oxadiazine dione reaction, 1) is preferred from the viewpoint of availability, and 2) is preferred from the viewpoint of safety.

[0080] The amount of imino-oxadiazinedione catalyst used is not particularly limited, but from the viewpoint of reactivity, it is preferably 5 ppm or more, more preferably 10 ppm or more, and even more preferably 20 ppm or more, in mass ratio with respect to the isocyanate monomer such as HDI, which is the raw material.

[0081] From the viewpoint of suppressing coloration and discoloration of the product and controlling the reaction, the amount of imino-oxadiazinedione catalyst used is preferably 5000 ppm or less, more preferably 2000 ppm or less, and even more preferably 500 ppm or less, in mass ratio with respect to the isocyanate monomer such as HDI, which is the raw material.

[0082] In other words, the amount of imino-oxadiazinedione catalyst used is preferably 5 ppm to 5000 ppm by mass ratio with respect to the isocyanate monomer such as HDI, which is the raw material, more preferably 10 ppm to 2000 ppm, and even more preferably 20 ppm to 500 ppm.

[0083] The reaction temperature for iminooxadiazinedione formation is not particularly limited, but from the viewpoint of reaction rate, 40°C or higher is preferred, 50°C or higher is more preferred, and 60°C or higher is even more preferred. The reaction temperature for iminooxadiazinedione conversion is preferably 150°C or lower, more preferably 120°C or lower, and even more preferably 110°C or lower, from the viewpoint of suppressing coloration and discoloration of the product. In other words, the reaction temperature for iminooxadiazinedione formation is preferably 40°C to 150°C, more preferably 50°C to 120°C, and even more preferably 60°C to 110°C.

[0084] The imino-oxadiazinedione reaction can be stopped when the desired imino-oxadiazinedione group content is reached. The reaction can be stopped, for example, by adding an acidic compound to the reaction solution. Examples of acidic compounds include phosphoric acid, acidic phosphoric acid esters, sulfuric acid, hydrochloric acid, and sulfonic acid compounds. This neutralizes the imino-oxadiazinedione reaction catalyst, or inactivates it by thermal or chemical decomposition. After stopping the reaction, filtration can be performed if necessary.

[0085] (4) Method for producing isocyanurate group-containing polyisocyanate Commonly used isocyanuration reaction catalysts can be used as catalysts for deriving polyisocyanates containing isocyanurate groups from isocyanate monomers.

[0086] The isocyanurate reaction catalyst is not particularly limited, but it is generally preferable that it is basic. Specific examples of isocyanurate reaction catalysts include those listed below.

[0087] 1) Hydroxides of tetraalkylammonium such as tetramethylammonium, tetraethylammonium, and tetrabutylammonium, and organic weak salts of the tetraalkylammonium such as acetate, propionate, octylate, caprine, myristicate, and benzoate. 2) Hydroxides of aryltrialkylammonium such as benzyltrimethylammonium and trimethylphenylammonium, and organic weak salts of the aryltrialkylammonium such as acetate, propionate, octylate, caprine, myristate, and benzoate. 3) Hydroxyalkylammonium hydroxides such as trimethylhydroxyethylammonium, trimethylhydroxypropylammonium, triethylhydroxyethylammonium, and triethylhydroxypropylammonium, and organic weak salts such as acetate, propionate, octylate, caprine, myristicate, and benzoate of the hydroxyalkylammonium.

[0088] 4) Metal salts of alkyl carboxylic acids such as acetic acid, propionic acid, caproic acid, octic acid, capric acid, and myristic acid, such as tin, zinc, and lead. 5) Metal alkoxides such as sodium and potassium. 6) Aminosilyl group-containing compounds such as hexamethylene disilazane. 7) Mannich bases. 8) A mixture of tertiary amines and epoxy compounds. 9) Phosphorus compounds such as tributylphosphine.

[0089] In particular, from the viewpoint of minimizing the generation of unwanted by-products, the isocyanurate reaction catalyst is preferably a quaternary ammonium hydroxide or a weak organic salt of a quaternary ammonium, and more preferably a tetraalkylammonium hydroxide, a weak organic salt of a tetraalkylammonium, an aryltrialkylammonium hydroxide, or a weak organic salt of an aryltrialkylammonium.

[0090] The amount of the isocyanurate reaction catalyst used is preferably 1000 ppm or less by mass, more preferably 500 ppm or less by mass, and even more preferably 100 ppm or less by mass, relative to the mass of the charged isocyanate monomer. On the other hand, there are no particular limitations on the amount of the isocyanurate reaction catalyst used, but for example, it may be 10 ppm or more by mass.

[0091] The isocyanuration reaction temperature is preferably 50°C to 120°C, and more preferably 60°C to 90°C. Keeping the isocyanuration reaction temperature below the above upper limit tends to more effectively suppress discoloration of the polyisocyanate.

[0092] When the desired conversion rate (the ratio of the mass of polyisocyanate produced by the isocyanuration reaction to the mass of the isocyanate monomer added) is reached, the isocyanuration reaction is stopped by adding an acidic compound (e.g., phosphoric acid, acidic phosphate ester, etc.).

[0093] Furthermore, in order to obtain polyisocyanates, it is necessary to stop the reaction in its initial stages. However, because the isocyanuration reaction has a very fast initial reaction rate, it is difficult to stop the reaction in its early stages, and the reaction conditions, especially the amount and method of catalyst addition, must be carefully selected. For example, a method of adding the catalyst in installments at regular intervals is recommended as a suitable approach.

[0094] Therefore, the conversion rate of the isocyanurate reaction to obtain polyisocyanate is preferably 10% to 60%, more preferably 15% to 55%, and even more preferably 20% to 50%.

[0095] By keeping the conversion rate of the isocyanurate reaction below the upper limit, the viscosity of the blocked polyisocyanate component can be reduced. Furthermore, by keeping the conversion rate of the isocyanurate reaction above the lower limit, the reaction termination operation can be made easier.

[0096] Furthermore, when deriving polyisocyanates containing isocyanurate groups, alcohols with a valency of 10 to 6 can be used in addition to the isocyanate monomers mentioned above. Examples of alcohols that can be used that are monovalent to hexavalent include non-polymerizable alcohols and polymerizable alcohols. Here, "non-polymerizable alcohol" means an alcohol that does not have polymerizable groups. On the other hand, "polymerizable alcohol" means an alcohol obtained by polymerizing monomers that have polymerizable groups and hydroxyl groups.

[0097] Examples of non-polymerizable alcohols include polyhydric alcohols such as monoalcohols, diols, triols, and tetraols. Examples of monoalcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, n-pentanol, n-hexanol, n-octanol, n-nonanol, 2-ethylbutanol, 2,2-dimethylhexanol, 2-ethylhexanol, cyclohexanol, methylcyclohexanol, and ethylcyclohexanol.

[0098] Examples of diols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,2-propanediol, 1,5-pentanediol, and 2-methyl-2,3-butanediol. Examples include tandiol, 1,6-hexanediol, 1,2-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentanediol, 2,3-dimethyl-2,3-butanediol, 2-ethyl-hexanediol, 1,2-octanediol, 1,2-decanediol, 2,2,4-trimethylpentanediol, 2-butyl-2-ethyl-1,3-propanediol, and 2,2-diethyl-1,3-propanediol.

[0099] Examples of triols include glycerol and trimethylolpropane. Examples of tetraols include pentaerythritol.

[0100] The polymerizable alcohol is not particularly limited, but examples include polyester polyols, polyether polyols, acrylic polyols, and polyolefin polyols. Polyester polyols are not particularly limited, but examples include products obtained by the condensation reaction of a dibasic acid (alone or a mixture) with a polyhydric alcohol (alone or a mixture).

[0101] The dibasic acid is not particularly limited, but examples include at least one dibasic acid selected from the group consisting of carboxylic acids such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, and terephthalic acid.

[0102] The polyhydric alcohol is not particularly limited, but examples include at least one polyhydric alcohol selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, and glycerol.

[0103] Furthermore, examples of polyester polyols include polycaprolactones obtained by ring-opening polymerization of ε-caprolactone using the above-mentioned polyhydric alcohol.

[0104] Polyether polyols are not particularly limited, but examples include polyether polyols obtained by adding an alkylene oxide alone or in a mixture to a polyhydric alcohol alone or in a mixture using an alkali metal hydroxide or a strongly basic catalyst, polyether polyols obtained by reacting a polyamine compound with an alkylene oxide, and so-called polymer polyols obtained by polymerizing acrylamide or the like using the above polyethers as a medium.

[0105] Examples of alkali metals include lithium, sodium, and potassium. Examples of strongly basic catalysts include alcoholates and alkylamines. Examples of polyhydric alcohols include those similar to those exemplified in the above-mentioned polyester polyols. Examples of alkylene oxides include ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, and styrene oxide. Examples of polyamine compounds include ethylenediamines.

[0106] Acrylic polyols are not particularly limited, but examples include those obtained by copolymerizing a monomer containing an ethylenically unsaturated bond having a hydroxyl group, either alone or in a mixture thereof, with another monomer containing an ethylenically unsaturated bond, either alone or in a mixture thereof, that can be copolymerized with the same.

[0107] The monomer containing an ethylenically unsaturated bond and having a hydroxyl group is not particularly limited, but examples include hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxybutyl methacrylate. Other ethylenically unsaturated bond-containing monomers copolymerizable with ethylenically unsaturated bond-containing monomers having hydroxyl groups are not particularly limited, but include, for example, acrylic acid esters, methacrylic acid esters, unsaturated carboxylic acids, unsaturated amides, vinyl monomers, and vinyl monomers having hydrolyzable silyl groups.

[0108] Examples of acrylic acid esters include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, benzyl acrylate, and phenyl acrylate.

[0109] Examples of methacrylic acid esters include methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, benzyl methacrylate, and phenyl methacrylate.

[0110] Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, and itaconic acid. Examples of unsaturated amides include acrylamide, methacrylamide, N,N-methylenebisacrylamide, diacetone acrylamide, diacetone methacrylamide, maleic acid amide, and maleimide.

[0111] Examples of vinyl monomers include glycidyl methacrylate, styrene, vinyltoluene, vinyl acetate, acrylonitrile, and dibutyl fumarate. Examples of vinyl monomers having hydrolyzable silyl groups include vinyltrimethoxysilane, vinylmethyldimethoxysilane, and γ-(meth)acryloxypropyltrimethoxysilane.

[0112] Examples of polyolefin polyols include terminally hydroxylated polybutadiene and its hydrogenated derivatives.

[0113] (5) Method for producing urethane group-containing polyisocyanate When deriving polyisocyanates containing urethane groups from isocyanate monomers, for example, they can be produced by mixing an excess isocyanate monomer with an alcohol and adding a urethane reaction catalyst as needed.

[0114] Examples of the aforementioned alcohols include those exemplified above as "alcohols with a base of 10 or more but with a base of 6 or less". The urethane reaction catalyst is not particularly limited, but examples include tin-based compounds, zinc-based compounds, amine-based compounds, and the like.

[0115] The urethane reaction temperature is preferably 50°C to 160°C, and more preferably 60°C to 120°C. By keeping the urethane reaction temperature below the above upper limit, discoloration of the polyisocyanate tends to be more effectively suppressed.

[0116] Furthermore, the urethane reaction time is preferably 30 minutes to 4 hours, more preferably 1 hour to 3 hours, and even more preferably 1 hour to 2 hours. The ratio of the molar amount of isocyanate groups in the isocyanate monomer to the molar amount of hydroxyl groups in the alcohol is preferably between 2 / 1 and 50 / 1. A molar ratio above the lower limit allows for a lower viscosity polyisocyanate. A molar ratio below the upper limit allows for a higher yield of the urethane group-containing polyisocyanate.

[0117] (6) Method for producing biuret group-containing polyisocyanate Biuretting agents for deriving polyisocyanates containing biuret groups from isocyanate monomers are not particularly limited, but examples include water, monohydric tertiary alcohols, formic acid, organic monoamines, organic diamines, and the like.

[0118] It is preferable to use 6 moles or more of isocyanate groups per mole of biuretizing agent, more preferably 10 moles or more, and even more preferably 10 moles or more and 80 moles or less. If the amount of isocyanate groups per mole of biuretizing agent is above the lower limit, the polyisocyanate will have sufficiently low viscosity, and if it is below the upper limit, the low-temperature curability of the resin film will be further improved.

[0119] Furthermore, a solvent may be used during the biuretization reaction. The solvent can be any solvent that dissolves the isocyanate monomer and a biuretizing agent such as water, and forms a homogeneous phase under the reaction conditions. Examples of the aforementioned solvents include ethylene glycol-based solvents and phosphoric acid-based solvents. Examples of ethylene glycol-based solvents include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-propyl ether acetate, ethylene glycol monoisopropyl ether acetate, ethylene glycol mono-n-butyl ether acetate, ethylene glycol diacetate, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol di-n-propyl ether, ethylene glycol diisopropyl ether, ethylene glycol di-n-butyl ether, ethylene glycol methyl ethyl ether, ethylene glycol methyl isopropyl ether, ethylene glycol methyl-n-butyl ether, ethylene glycol ethyl-n-propyl ether, ethylene glycol ethyl isopropyl ether, ethylene glycol ethyl-n-butyl ether, ethylene glycol-n-propyl-n-butyl ether, ethylene glycol isopropyl-n-butyl ether, and diethylene glycol monomethyl Examples include ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-propyl ether acetate, diethylene glycol monoisopropyl ether acetate, diethylene glycol mono-n-butyl ether acetate, diethylene glycol diacetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol di-n-propyl ether, diethylene glycol diisopropyl ether, diethylene glycol di-n-butyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl isopropyl ether, diethylene glycol methyl-n-propyl ether, diethylene glycol methyl-n-butyl ether, diethylene glycol ethyl isopropyl ether, diethylene glycol ethyl-n-propyl ether, diethylene glycol ethyl-n-butyl ether, diethylene glycol-n-propyl-n-butyl ether, and diethylene glycol isopropyl-n-butyl ether.

[0120] Examples of phosphoric acid-based solvents include trimethyl phosphate, triethyl phosphate, tripropyl phosphate, and tributyl phosphate. These solvents may be used individually or in combination of two or more. Among these, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol diacetate, or diethylene glycol dimethyl ether are preferred as ethylene glycol-based solvents. Furthermore, trimethyl phosphate or triethyl phosphate are preferred as the phosphoric acid-based solvent.

[0121] The biuretization reaction temperature is preferably between 70°C and 200°C, and more preferably between 90°C and 180°C. Keeping the temperature below the above upper limit tends to more effectively prevent discoloration of the polyisocyanate.

[0122] The allophanate reaction, uretdione reaction, iminooxadiazinedione reaction, isocyanurate reaction, urethane reaction, and biuret reaction described above may be carried out sequentially, or some of them may be carried out in parallel. After the reaction is complete, unreacted isocyanate monomers can be removed from the reaction solution by thin-film distillation, extraction, or other methods to obtain polyisocyanate.

[0123] The average number of isocyanate groups in the polyisocyanate is 3.5 or more, preferably 4.0 or more, more preferably 4.5 or more, and even more preferably 4.7 or more. Having an average number of isocyanate groups equal to or above the lower limit of the above value results in excellent curability, hardness, and strength at low temperatures of around 80°C when used as a coating film. On the other hand, the upper limit of the average number of isocyanate groups in the polyisocyanate is not limited; for example, it can be 20, 10, or 8.

[0124] The average number of isocyanate groups in a polyisocyanate can be determined, for example, from the number-average molecular weight Mn and the isocyanate group content (NCO content) of the polyisocyanate using the following formula. Average number of isocyanate groups = (Mn × NCO content of polyisocyanate × 0.01) / 42

[0125] The number-average molecular weight (Mn) of polyisocyanate is, for example, the number-average molecular weight relative to polystyrene, measured by GPC. Specifically, it can be measured using the method described in the examples below.

[0126] The isocyanate group content (NCO content) can be measured, for example, using the method shown below. Accurately weigh 2 g to 3 g of polyisocyanate into a flask (Wg). Then, add 20 mL of toluene to dissolve the polyisocyanate. Next, add 20 mL of toluene solution of 2 N di-n-butylamine, mix, and let stand at room temperature for 15 minutes. Next, add 70 mL of isopropyl alcohol and mix. Then, titrate this solution with 1 N hydrochloric acid solution (factor F) on an indicator. The obtained titration value is V2 mL. Next, the titration value obtained without polyisocyanate is V1 mL. Next, calculate the isocyanate group (NCO) content (mass%) of the polyisocyanate using the following formula. Isocyanate group (NCO) content (mass%) = (V1-V2) × F × 42 / (W × 1000) × 100

[0127] The polyisocyanate is preferably derived from the diisocyanate and a polyol having an average number of functional groups of 2.9 or more and 8.0 or less. This allows for a larger average number of isocyanate groups in the resulting polyisocyanate. In this polyisocyanate, urethane groups are formed by the reaction of the hydroxyl groups of the polyol with the isocyanate groups of the diisocyanate.

[0128] The average number of functional groups in a polyol is preferably 2.9 to 8.0, more preferably 3 to 8, even more preferably 3 to 6, even more preferably 3 to 5, and particularly preferably 3 or 4. The average number of functional groups in a polyol can be calculated, for example, using the following formula. In the formula, "Mn" represents the number-average molecular weight of the polyol, "hydroxyl group content" represents the content of hydroxyl groups (mass%) relative to 100% mass of the solid content of the polyol, and "17" represents the molecular weight of the hydroxyl group (g / mol). (Average number of functional groups in a polyol) = {(Mn of the polyol) × (Hydroxyl group content) × 0.01} / 17

[0129] The number-average molecular weight Mn of the polyol is preferably 100 to 1000, more preferably 100 to 900, more preferably 100 to 800, even more preferably 100 to 700, even more preferably 100 to 500, even more preferably 100 to 400, and particularly preferably 100 to 350.

[0130] When the number-average molecular weight (Mn) of the polyol is within the above range, the block polyisocyanate composition exhibits superior hardness and strength when used as a resin film. The number-average molecular weight (Mn) of the polyol is, for example, the number-average molecular weight of polystyrene measured by GPC.

[0131] Examples of polyols include trimethylolpropane, glycerol, and polycaprolactone polyols derived from trivalent or higher polyhydric alcohols and ε-caprolactone. Examples of commercially available polycaprolactone polyols include Daicel's "Praxel 303" (number average molecular weight 300), "Praxel 305" (number average molecular weight 550), "Praxel 308" (number average molecular weight 850), and "Praxel 309" (number average molecular weight 900).

[0132] Furthermore, antioxidants or UV absorbers may be added to the obtained polyisocyanate, for example, to suppress discoloration during storage. Examples of antioxidants include hindered phenols such as 2,6-di-tert-butyl-p-cresol. Examples of ultraviolet absorbers include benzotriazole and benzophenone. These antioxidants and ultraviolet absorbers may be used individually or in combination of two or more. The amount of these added is preferably 10 ppm by mass or more and 500 ppm by mass or less, relative to the mass of the polyisocyanate.

[0133] [Hydrophilic compound] At least a portion of the blocked polyisocyanate may have constituent units derived from hydrophilic compounds, i.e., hydrophilic groups.

[0134] Hydrophilic compounds are compounds that have hydrophilic groups. Preferably, hydrophilic compounds have, in addition to hydrophilic groups, one or more active hydrogen groups per molecule of the hydrophilic compound for reacting with at least one isocyanate group of the polyisocyanate. Specific examples of active hydrogen groups include hydroxyl groups, mercapto groups, carboxylic acid groups, amino groups, and thiol groups.

[0135] Examples of hydrophilic compounds include nonionic compounds, cationic compounds, and anionic compounds. These hydrophilic compounds may be used individually or in combination of two or more. Among these, nonionic compounds are preferred as hydrophilic compounds from the viewpoint of ease of availability and low electrical interaction with the compound, while anionic compounds are preferred from the viewpoint of suppressing a decrease in the hardness of the resulting resin film.

[0136] (Nonionic compounds) Nonionic compounds specifically include monoalcohols and compounds obtained by adding ethylene oxide to the hydroxyl group of an alcohol. Examples of monoalcohols include methanol, ethanol, and butanol. Examples of compounds obtained by adding ethylene oxide to the hydroxyl group of an alcohol include ethylene glycol, diethylene glycol, and polyethylene glycol. These nonionic compounds also possess active hydrogen groups that react with isocyanate groups.

[0137] Among nonionic compounds, polyethylene glycol monoalkyl ethers, which are obtained by adding ethylene oxide to the hydroxyl group of a monoalcohol, are preferred because they can improve the water dispersibility of the blocked polyisocyanate composition with a small amount of use.

[0138] The number of ethylene oxide atoms added to the compound is preferably 4 to 30, and more preferably 4 to 25. When the number of ethylene oxide atoms is above the lower limit, the block polyisocyanate composition tends to be more effectively given water dispersibility, and when the number of ethylene oxide atoms is below the upper limit, precipitates of the block polyisocyanate composition tend to be less likely to occur during low-temperature storage.

[0139] The amount of nonionic hydrophilic groups added to the blocked polyisocyanate (hereinafter sometimes referred to as "nonionic hydrophilic group content") is preferably 0.1% by mass or more, more preferably 0.15% by mass or more, even more preferably 0.20% by mass or more, and particularly preferably 0.25% by mass or more, relative to the mass of the solid content of the hydrophilic polyisocyanate composition, from the viewpoint of the water dispersion stability of the blocked polyisocyanate composition.

[0140] Furthermore, from the viewpoint of the water resistance of the resulting resin film, the content of nonionic hydrophilic groups is preferably 55% by mass or less, more preferably 50% by mass or less, even more preferably 48% by mass or less, and particularly preferably 44% by mass or less, based on the mass of the solid content of the block polyisocyanate composition.

[0141] In other words, the content of nonionic hydrophilic groups is preferably 0.1% to 55% by mass, more preferably 0.15% to 50% by mass, even more preferably 0.20% to 48% by mass, and particularly preferably 0.25% to 44% by mass, based on the mass of the solid content of the block polyisocyanate composition.

[0142] When the content of nonionic hydrophilic groups is within the above range, the blocked polyisocyanate composition tends to disperse more easily in water, resulting in a more homogeneous film.

[0143] When expressing the amount of nonionic hydrophilic groups added to the block polyisocyanate as a molar ratio, it is preferably 0.05 mol% to 8 mol%, more preferably 0.10 mol% to 5 mol%, even more preferably 0.15 mol% to 4 mol%, particularly preferably 0.15 mol% to 3 mol%, and most preferably 0.15 mol% to 2 mol% relative to 100 mol% of isocyanate groups in the raw material polyisocyanate.

[0144] (Cationic compounds) Specifically, cationic compounds include compounds having both a cationic hydrophilic group and an active hydrogen group. Alternatively, a hydrophilic compound may be formed by combining a compound having an active hydrogen group, such as a glycidyl group, with a compound having a cationic hydrophilic group, such as a sulfide or phosphine. In this case, a compound having an isocyanate group and a compound having an active hydrogen group are reacted beforehand to add a functional group such as a glycidyl group, and then the compound such as a sulfide or phosphine is reacted. From the viewpoint of ease of production, compounds having both a cationic hydrophilic group and an active hydrogen group are preferred.

[0145] Examples of compounds possessing both a cationic hydrophilic group and an active hydrogen group include dimethylethanolamine, diethylethanolamine, diethanolamine, and methyldiethanolamine. Furthermore, the tertiary amino groups added using these compounds can be quaternized with, for example, dimethyl sulfate or diethyl sulfate.

[0146] The reaction between cationic compounds and alicyclic polyisocyanates can be carried out in the presence of a solvent. In this case, the solvent is preferably one that does not contain active hydrogen groups, and specific examples include ethyl acetate, propylene glycol monomethyl ether acetate, and dipropylene glycol dimethyl ether.

[0147] The cationic hydrophilic group added to the blocked polyisocyanate is preferably neutralized with a compound having an anionic group. Specific examples of such anionic groups include carboxyl groups, sulfonic acid groups, phosphoric acid groups, halogen groups, and sulfate groups.

[0148] Examples of compounds containing a carboxyl group include formic acid, acetic acid, propionic acid, butyric acid, and lactic acid. Examples of compounds having a sulfonic acid group include, for instance, ethanesulfonic acid. Examples of compounds containing a phosphate group include, for example, phosphoric acid and acidic phosphate esters. Examples of compounds containing halogen groups include hydrochloric acid. Examples of compounds containing a sulfate group include sulfuric acid. Among the compounds having anionic groups, compounds having a carboxyl group are preferred, and acetic acid, propionic acid, or butyric acid are more preferred.

[0149] (Anionic compounds) Examples of anionic hydrophilic groups include carboxyl groups, sulfonic acid groups, phosphoric acid groups, halogen groups, and sulfate groups. Examples of anionic compounds include compounds that have both an anionic group and an active hydrogen group, and more specifically, compounds in which the carboxyl group of a monohydroxycarboxylic acid or polyhydroxycarboxylic acid is the anionic group.

[0150] Examples of monohydroxycarboxylic acids include 1-hydroxyacetic acid, 3-hydroxypropanoic acid, 12-hydroxy-9-octadecanoic acid, hydroxypivalic acid (hydroxypivalic acid), and lactic acid.

[0151] Examples of compounds having a polyhydroxycarboxylic acid carboxyl group as an anionic group include dimethylolacetic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolpentanoic acid, dihydroxysuccinic acid, and dimethylolpropionic acid.

[0152] Furthermore, compounds having both a sulfonic acid group and an active hydrogen group can also be cited, more specifically, isethionic acid, for example. Among these, hydroxypivalic acid or dimethylolpropionic acid are preferred as compounds having both an anionic group and an active hydrogen group.

[0153] It is preferable to neutralize the anionic hydrophilic group added to the blocked polyisocyanate with an amine compound, which is a basic substance. Examples of amine compounds include ammonia and water-soluble amino compounds. Examples of water-soluble amino compounds include monoethanolamine, ethylamine, dimethylamine, diethylamine, triethylamine, propylamine, dipropylamine, isopropylamine, diisopropylamine, triethanolamine, butylamine, dibutylamine, 2-ethylhexylamine, ethylenediamine, propylenediamine, methylethanolamine, dimethylethanolamine, diethylethanolamine, and morpholine. Tertiary amines such as triethylamine and dimethylethanolamine can also be used. These amine compounds may be used individually or in combination of two or more.

[0154] [Blocking agent] The blocking agent contains a malonic acid diester. As the malonic acid diester, for example, a malonic acid diester having primary, secondary, and tertiary alkyl groups as described below can be used.

[0155] There are no particular limitations on the malonic acid diester having a primary alkyl group, but examples include dimethyl malonate, diethyl malonate, dipropyl malonate, dibutyl malonate, dicyclohexyl malonate, and diphenyl malonate. Among these, diethyl malonate is preferred as the malonic acid diester having a primary alkyl group.

[0156] There are no particular limitations on the malonic acid diester having a secondary alkyl group, but examples include di-sec-butyl malonate, diisopropyl malonate, and isopropylethyl malonate. Among these, diisopropyl malonate is preferred as the malonic acid diester having a secondary alkyl group.

[0157] There are no particular limitations on malonic acid diesters having a tertiary alkyl group, but examples include di-tert-butyl malonate, di(2-methyl-2-butyl) malonate, di(2-methyl-2-pentyl) malonate, (tert-butyl) ethyl malonate, (2-methyl-2-butyl) ethyl malonate, (2-methyl-2-butyl) isopropyl malonate, (2-methyl-2-pentyl) ethyl malonate, (2-methyl-2-pentyl) isopropyl malonate, and (2-methyl-2-pentyl) hexyl isopropyl malonate. Among these, di(2-methyl-2-butyl) malonate, di(2-methyl-2-pentyl) malonate, isopropyl (2-methyl-2-butyl) malonate, ethyl (2-methyl-2-pentyl) malonate, and isopropyl (2-methyl-2-pentyl) malonate are preferred, as are ethyl (2-methyl-2-butyl) malonate, isopropyl (2-methyl-2-butyl) malonate, ethyl (2-methyl-2-pentyl) malonate, and hexyl isopropyl (2-methyl-2-pentyl) malonate, or di-tert-butyl malonate, isopropyl (2-methyl-2-butyl) malonate, or isopropyl (2-methyl-2-pentyl) malonate.

[0158] The malonic acid diester having a tertiary alkyl group may be a commercially available product, or it may be synthesized using the method described in Reference 1 (Japanese Patent Publication No. 11-130728).

[0159] (Other blocking agents) In addition to malonic acid diester, the blocking agent used in the production of blocked polyisocyanates may also contain other blocking agents, provided that they do not impair the storage stability of the resin composition or the low-temperature curing properties of the resin film.

[0160] Other blocking agents include, for example, 1) alcohol compounds, 2) alkylphenol compounds, 3) phenol compounds, 4) active methylene compounds other than malonic acid diesters having a secondary alkyl group and malonic acid diesters having a tertiary alkyl group, 5) mercaptan compounds, 6) acid amide compounds, 7) acid imide compounds, 8) imidazole compounds, 9) urea compounds, 10) oxime compounds, 11) amine compounds, 12) imide compounds, 13) bisulfites, 14) pyrazole compounds, and 15) triazole compounds. More specifically, the following are examples of blocking agents.

[0161] 1) Alcohol compounds: Alcohols such as methanol, ethanol, 2-propanol, n-butanol, sec-butanol, 2-ethyl-1-hexanol, 2-methoxyethanol, 2-ethocacyethanol, and 2-butoxyethanol. 2) Alkylphenol compounds: Monoalkylphenols and dialkylphenols having an alkyl group with 4 or more carbon atoms as a substituent. Specifically, examples of alkylphenol compounds include monoalkylphenols such as n-propylphenol, iso-propylphenol, n-butylphenol, sec-butylphenol, tert-butylphenol, n-hexylphenol, 2-ethylhexylphenol, n-octylphenol, and n-nonylphenol; and dialkylphenols such as di-n-propylphenol, diisopropylphenol, isopropyl cresol, di-n-butylphenol, di-tert-butylphenol, di-sec-butylphenol, di-n-octylphenol, di-2-ethylhexylphenol, and di-n-nonylphenol.

[0162] 3) Phenolic compounds: Phenol, cresol, ethylphenol, styrene-phenol, hydroxybenzoic acid esters, etc. 4) Active methylene compounds: Dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, methyl isobutanoylacetate, ethyl isobutanoylacetate, acetylacetone, etc. 5) Mercaptan compounds: butyl mercaptan, dodecyl mercaptan, etc. 6) Acid amide compounds: acetanilide, acetic acid amide, ε-caprolactam, δ-valerolactam, γ-butyrolactam, etc. 7) Acidimide compounds: succinimide, maleimide, etc. 8) Imidazole compounds: imidazole, 2-methylimidazole, etc. 9) Urea compounds: Urea, thiourea, ethyleneurea, etc. 10) Oxime compounds: formaldehyde oxime, acetaldehyde oxime, acetoxime, methyl ethyl ketoxime, cyclohexanone oxime, etc. 11) Amine compounds: diphenylamine, aniline, carbazole, di-n-propylamine, diisopropylamine, isopropylethylamine, etc. 12) Imine compounds: Ethyleneimine, polyethyleneimine, etc. 13) Bisulfite compounds: Sodium bisulfite, etc. 14) Pyrazole compounds: pyrazole, 3-methylpyrazole, 3,5-dimethylpyrazole, etc. 15) Triazole compounds: 3,5-dimethyl-1,2,4-triazole, etc.

[0163] (Other components) The blocked polyisocyanate composition of this embodiment may further contain additives such as solvents in addition to the blocked polyisocyanate.

[0164] Examples of solvents include 1-methylpyrrolidone, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether, 3-methoxy-3-methyl-1-butanol, ethylene glycol diethyl ether, diethylene glycol diethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether (DPDM), propylene glycol dimethyl ether, methyl ethyl ketone, and acetone. Examples of solvents include methyl isobutyl ketone, propylene glycol monomethyl ether acetate, ethanol, methanol, iso-propanol, 1-propanol, iso-butanol, 1-butanol, tert-butanol, 2-ethylhexanol, cyclohexanol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, ethyl acetate, isopropyl acetate, butyl acetate, toluene, xylene, pentane, iso-pentane, hexane, iso-hexane, cyclohexane, solvent naphtha, mineral spirits, etc. These solvents may be used individually or in combination of two or more. From the viewpoint of dispersibility in water, solvents with a solubility in water of 5% by mass or more are preferred, and specifically, DPDM is preferred.

[0165] (Polar solvent) The block polyisocyanate composition of this embodiment preferably contains a polar solvent. The polar solvent included in the block polyisocyanate composition of this embodiment is preferably a compound with a high SP value and strong polarity. The "SP value (δ)" referred to here is defined as the square root of the cohesive energy density expressed by the following equation (1). δ = (ΔE / V)¹ / ² ···(1) In equation (1), V is the molar volume of the solvent, and ΔE is the cohesive energy (evaporation energy). Generally, the SI units for SP values ​​are (J / cm³)¹ / ² and (MPa)¹ / ², but in this specification, the conventionally used (cal / cm³)¹ / ² is used.

[0166] ΔE is related to the enthalpy of evaporation ΔH by equation (2). Also, PΔT = RT. Therefore, equation (3) can be obtained from equations (1) and (2). ΔH = ΔE + PΔV ... (2) δ = [(ΔH - RT) / V] 1 / 2 ... (3) Therefore, the SP value can be calculated from the latent heat of vaporization required for 1 cm³ of liquid to evaporate.

[0167] In particular, as polar solvents, compounds with an SP value of 7.5 or higher are preferred, compounds with an SP value of 9.0 or higher are more preferred, and compounds with an SP value of 10.0 or higher are even more preferred. Examples of polar solvents are listed below.

[0168] (1) Ketones such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, and methylcyclohexanone; (2) Aldehydes such as acetaldehyde, butyraldehyde, and benzaldehyde; Nitriles such as acetonitrile, butyronitrile, and caprylnitrile; (3) Esters such as methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, dimethyl phthalate, diethyl phthalate, dipropyl phthalate, dibutyl phthalate, diamyl phthalate, dibutyl fumarate, dimethyl maleate, diethyl maleate, and dibutyl maleate; (4) Ethers such as furan, tetrahydrofuran, propyl oxide, dioxane, dibenzyl ether, and diphenyl ether; (5) Glycol ether esters such as ethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, cyclohexanol acetate, propylene glycol diacetate, 1,4-butanediol diacetate, 1,3-butylene glycol diacetate, and 1,6-hexanediol diacetate; (6) Hydrocarbons such as isophorones and benzenes; (7) Phosphite esters such as triphenyl phosphite; (8) Sulfur compounds such as dimethyl sulfide, thiophene, and carbon disulfide; (9) Halogenated hydrocarbons such as methyl chloride, ethyl chloride, dichloropropane, dichloroethylene, trichloroethylene, tetrachloroethylene, pentachloroethane, chloroform, methyl bromide, ethyl bromide, methyl iodide, and ethyl iodide; (10) Primary monoalcohols such as methanol, ethanol, propanol, butanol, hexanol, and 2-ethylhexanol; secondary monoalcohols such as isopropanol, 2-butanol, 2-pentanol, and 2-hexanol; and tertiary monoalcohols such as tert-butanol, 2-methyl-2-butanol, 2-methyl-2-pentanol, 2-methyl-2-hexanol, 2-methyl-2-heptanol, 2-methyl-2-octanol, 3-methyl-3-pentanol, 3-ethyl-3-hexanol, and 3-ethyl-3-octanol;

[0169] The mass ratio of the block polyisocyanate to the polar solvent in the block polyisocyanate composition of this embodiment is preferably 99 / 1 to 1 to 99, more preferably 97 / 3 to 60 / 40, and even more preferably 95 / 5 to 80 / 20.

[0170] When the polar solvent is above the lower limit, the stability of the blocked polyisocyanate composition is improved, and when it is below the upper limit, thickening during formulation with water-based paints can be suppressed. Furthermore, when using alcohols as polar solvents, tertiary monoalcohols are preferred from the viewpoint of curability at low temperatures.

[0171] ≪Method for producing blocked polyisocyanate compositions≫ The method for producing the blocked polyisocyanate composition of this embodiment is not particularly limited, but similar to the blocking reaction between the polyisocyanate and the blocking agent, there are two methods as shown below. 1) A method for reacting the above polyisocyanate with the above malonic acid diester. 2) A method of reacting the above polyisocyanate with at least one blocking agent selected from the group consisting of malonic acid diester having a tertiary alkyl group, malonic acid diester having a secondary alkyl group, and malonic acid diester having a primary alkyl group, and adding an alcohol having a chain alkyl group to the resulting reaction product to introduce an alkyl group derived from the alcohol by transesterification of the terminal ester portion of the reaction product.

[0172] Of the two methods described above, method 2) is preferred, considering the ease of the process, the content of constituent unit (I-2-1), and the ease of controlling the content of constituent unit (I-3-1).

[0173] The blocking reaction between polyisocyanate and a blocking agent can be carried out with or without the presence of a solvent, yielding blocked polyisocyanate. The amount of blocking agent added is usually 80 mol% to 200 mol%, and preferably 90 mol% to 150 mol%, relative to the total molar amount of isocyanate groups.

[0174] When using a solvent, it is sufficient to use a solvent that is inert to the isocyanate group. When a solvent is used, the content of non-volatile components per 100 parts by mass of the blocked polyisocyanate composition may be 10 parts by mass or more and 95 parts by mass or less, preferably 20 parts by mass or more and 80 parts by mass or less, and more preferably 30 parts by mass or more and 75 parts by mass or less.

[0175] In the blocking reaction, organometallic salts such as tin, zinc, and lead, tertiary amine compounds, and alkali metal alkoxides such as sodium may be used as catalysts. The amount of catalyst added varies depending on the temperature of the blocking reaction, but is usually between 0.05 parts by mass and 1.5 parts by mass per 100 parts by mass of polyisocyanate, and preferably between 0.1 parts by mass and 1.0 part by mass. Being within this range provides superior stability for the blocked polyisocyanate composition. When using a catalyst, it is preferable to deactivate it with an acidic compound to ensure the manufacturing stability of the blocked polyisocyanate composition.

[0176] Examples of acidic compounds include carboxylic acids, sulfonic acids, and acidic phosphate esters. Examples of carboxylic acids include acetic acid, lactic acid, succinic acid, oxalic acid, maleic acid, and decanedicarboxylic acid. Examples of sulfonic acids include p-toluenesulfonic acid, dodecylbenzenesulfonic acid, and dinonylnaphthalenedisulfonic acid. Examples of acidic phosphate esters include dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate, dilauryl phosphate, monomethyl phosphate, monoethyl phosphate, monobutyl phosphate, and monooctyl phosphate.

[0177] Among these, acidic phosphate esters are preferred, and acidic phosphate esters of dialkyl esters are particularly preferred from the viewpoint of the stability of the blocked polyisocyanate composition.

[0178] The blocking reaction can generally be carried out at temperatures between -20°C and 150°C, preferably between 0°C and 100°C, and more preferably between 10°C and 80°C. A temperature above the lower limit of the blocking reaction allows for a higher reaction rate, while a temperature below the upper limit allows for greater suppression of side reactions. After the blocking reaction, neutralization treatment may be performed by adding an acidic compound or the like.

[0179] As the acidic compound, inorganic acids or organic acids may be used. Examples of inorganic acids include hydrochloric acid, phosphorous acid, and phosphoric acid. Examples of organic acids include methanesulfonic acid, p-toluenesulfonic acid, dioctyl phthalate, and dibutyl phthalate.

[0180] Furthermore, when using hydrophilic compounds, the reaction between the polyisocyanate and the hydrophilic compound, and the reaction between the polyisocyanate and the blocking agent can be carried out simultaneously, or the second and subsequent reactions can be carried out after either reaction has been performed first. In particular, it is preferable to carry out the reaction between the polyisocyanate and the hydrophilic compound first to obtain a hydrophilic compound-modified polyisocyanate, and then to carry out the reaction between the obtained hydrophilic compound-modified polyisocyanate and the blocking agent.

[0181] The reaction between polyisocyanates and hydrophilic compounds may be catalyzed with organometallic salts, tertiary amine compounds, or alkali metal alkoxides. Examples of metals constituting the organometallic salts include tin, zinc, and lead. Examples of alkali metals include sodium.

[0182] The reaction temperature between polyisocyanate and hydrophilic compound is preferably between -20°C and 150°C, and more preferably between 30°C and 130°C. A reaction temperature above the lower limit tends to result in higher reactivity. Conversely, a reaction temperature below the upper limit tends to more effectively suppress side reactions.

[0183] It is preferable to completely react the hydrophilic compound with the polyisocyanate so that no unreacted residue remains. By ensuring that no unreacted residue remains, the decrease in the water dispersion stability of the blocked polyisocyanate composition and the low-temperature curability when formed into a resin film tend to be more effectively suppressed.

[0184] The reaction between the hydrophilic compound-modified polyisocyanate and the blocking agent can be carried out using the method described above as the blocking reaction.

[0185] When manufactured by the method described in (2) above, a transesterification reaction is carried out following the blocking reaction. 2) The alcohol having a chain alkyl group used in the transesterification reaction is preferably a monoalcohol, such as primary monoalcohols like methanol, ethanol, propanol, butanol, hexanol, and 2-ethylhexanol; secondary monoalcohols like isopropanol, 2-butanol, 2-pentanol, and 2-hexanol; and tertiary monoalcohols like tert-butanol, 2-methyl-2-butanol, 2-methyl-2-pentanol, 2-methyl-2-hexanol, 2-methyl-2-heptanol, 2-methyl-2-octanol, 3-methyl-3-pentanol, 3-ethyl-3-hexanol, and 3-ethyl-3-octanol.

[0186] Furthermore, the linear alkyl group of the alcohol may be the same as that of the blocking agent, or it may be a different linear alkyl group. If the linear alkyl group is different from that of the blocking agent, it is preferable to use a monoalcohol having a linear alkyl group with a different number of alkyl substitutions than that of the blocking agent. Specifically, for example, if a malonic acid diester having a secondary alkyl group is used alone as the blocking agent, a monoalcohol having a tertiary alkyl group can be used.

[0187] When manufacturing by method 2), it is preferable to remove any residual alcohol produced or added during or after the transesterification reaction by distillation at atmospheric pressure or under reduced pressure.

[0188] Among these, in order to allow the transesterification reaction to proceed efficiently, it is preferable to remove the generated alcohol by performing an operation such as distillation during the transesterification reaction. In this case, in order to efficiently remove the alcohol component generated by the transesterification reaction, it is more preferable that the added alcohol component has a boiling point higher than that of the generated alcohol component.

[0189] The transesterification reaction can generally be carried out at 0°C or higher and 150°C or lower, preferably 30°C or higher and 120°C or lower, and more preferably 50°C or higher and 100°C or lower. When the temperature of the transesterification reaction is not lower than the above lower limit, the reaction rate can be further increased, and when the temperature is not higher than the above upper limit, side reactions can be further suppressed.

[0190] The content of the alcohol component in the blocked polyisocyanate composition is preferably 0.05 to 41 parts by mass, more preferably 0.1 to 30 parts by mass, and even more preferably 0.5 to 10 parts by mass, relative to 100 parts by mass of the solid content of the blocked polyisocyanate composition. When the content of the alcohol component is not lower than the above lower limit, the storage stability of the coating becomes favorable, and when the content is not higher than the above upper limit, thickening during the formulation of an aqueous coating can be suppressed.

[0191] The molar ratio of structural units (I-1), (I-2) and (I-3) to structural unit (I) can be controlled by adjusting the molar ratio of the alcohol added relative to the blocked isocyanate groups, or adjusting the transesterification reaction temperature and transesterification reaction time, distilling off the generated alcohol, or the like.

[0192] <Resin Composition> The resin composition of the present embodiment includes the blocked polyisocyanate composition of the present embodiment described above and a polyhydric hydroxy compound. The resin composition of the present embodiment can also be referred to as a one-component resin composition including a curing agent component and a main agent component.

[0193] The resin composition of the present embodiment has good storage stability, and is excellent in curability at a low temperature of about 80° C. when formed into a coating film. In addition, the resin composition of the present embodiment is excellent in storage stability when prepared as an aqueous resin composition, and thus is particularly suitably used as an aqueous resin composition. The constituent components of the resin composition of the present embodiment will be described in detail below.

[0194] <<Polyhydroxy Compound>> In this specification, the "polyhydroxy compound" means a compound having at least two hydroxy groups (hydroxyl groups) in one molecule, and is also referred to as a "polyol". Specific examples of the polyhydroxy compound include aliphatic hydrocarbon polyols, polyether polyols, polyester polyols, epoxy resins, fluorine-containing polyols, acrylic polyols, and the like. Among these, the polyhydroxy compound is preferably a polyester polyol, a fluorine-containing polyol or an acrylic polyol.

[0195] [Aliphatic Hydrocarbon Polyols] Examples of the aliphatic hydrocarbon polyols include terminal hydroxylated polybutadiene and hydrogenated products thereof.

[0196] [Polyether Polyols] Examples of the polyether polyols include those obtained by any one of the following methods (1) to (3). (1) Polyether polyols or polytetramethylene glycols obtained by adding an alkylene oxide, alone or as a mixture, to a polyhydric alcohol, alone or as a mixture. (2) Polyether polyols obtained by reacting an alkylene oxide with a polyfunctional compound. (3) So-called polymer polyols obtained by polymerizing acrylamide or the like using the polyether polyol obtained in (1) or (2) as a medium. Examples of the aforementioned polyhydric alcohols include glycerol and propylene glycol.

[0197] Examples of the alkylene oxide include ethylene oxide and propylene oxide. Examples of the aforementioned polyfunctional compounds include ethylenediamines and ethanolamines.

[0198] [Polyester polyols] Examples of the aforementioned polyester polyols include the polyester polyols of either (1) or (2) below. (1) Polyester polyol resins obtained by a condensation reaction of a dibasic acid alone or a mixture of two or more dibasic acids with a polyhydric alcohol alone or a mixture of two or more polyhydric alcohols. (2) Polycaprolactones obtained by ring-opening polymerization of ε-caprolactone with a polyhydric alcohol. Examples of the aforementioned dibasic acids include succinic acid, adipic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid, and carboxylic acids such as 1,4-cyclohexanedicarboxylic acid.

[0199] Examples of the aforementioned polyhydric alcohols include ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, trimethylpentanediol, cyclohexanediol, trimethylolpropane, glycerol, pentaerythritol, 2-methylolpropanediol, and ethoxylated trimethylolpropane.

[0200] [Epoxy resins] Examples of the epoxy resins include novolac-type epoxy resins, β-methylepiclo-type epoxy resins, cyclic oxirane-type epoxy resins, glycidyl ether-type epoxy resins, glycol ether-type epoxy resins, epoxy-type aliphatic unsaturated compounds, epoxidized fatty acid esters, ester-type polycarboxylic acids, aminoglycidyl-type epoxy resins, halogenated epoxy resins, resorcinol-type epoxy resins, and resins obtained by modifying these epoxy resins with amino compounds, polyamide compounds, etc.

[0201] [Fluorine-containing polyols] Examples of the fluorine-containing polyols include copolymers of fluoroolefins, cyclohexyl vinyl ethers, hydroxyalkyl vinyl ethers, and vinyl monocarboxylate esters, as disclosed in Reference 1 (Japanese Patent Publication No. 57-34107) and Reference 2 (Japanese Patent Publication No. 61-275311).

[0202] [Acrylic polyols] The aforementioned acrylic polyols can be obtained, for example, by polymerizing a polymerizable monomer having one or more active hydrogen atoms in one molecule, or by copolymerizing a polymerizable monomer having one or more active hydrogen atoms in one molecule with, if necessary, another monomer copolymerizable with the polymerizable monomer.

[0203] Examples of polymerizable monomers having one or more active hydrogen atoms in a single molecule include those listed in (i) to (iii) below. These may be used individually or in combination of two or more. (i) Acrylic acid esters containing active hydrogen, such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 2-hydroxybutyl acrylate. (ii) Methacrylic acid esters containing active hydrogen, such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 2-hydroxybutyl methacrylate. (iii) (meth)acrylic acid esters having a polyvalent active hydrogen, such as acrylic acid monoester or methacrylic acid monoester of glycerol, and acrylic acid monoester or methacrylic acid monoester of trimethylolpropane.

[0204] Examples of other monomers copolymerizable with the polymerizable monomer include those shown in the following (i) to (v). These may be used alone, or may be used in combination of two or more thereof. (i) acrylic acid esters such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate. (ii) methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, lauryl methacrylate, and glycidyl methacrylate. (iii) unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, and itaconic acid. (iv) unsaturated amides such as acrylamide, N-methylolacrylamide, and diacetone acrylamide. (v) styrene, vinyl toluene, vinyl acetate, acrylonitrile, etc.

[0205] Further, acrylic polyols obtained by copolymerizing polymerizable ultraviolet-stable monomers disclosed in Reference Document 3 (Japanese Unexamined Patent Publication No. Hei 1-261409) and Reference Document 4 (Japanese Unexamined Patent Publication No. Hei 3-006273) are also exemplified.

[0206] Specific examples of the polymerizable ultraviolet-stable monomer include 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 2-hydroxy-4-(3-methacryloxy-2-hydroxypropoxy)benzophenone, and the like.

[0207] For example, an acrylic polyol can be obtained by solution polymerization of the above monomer components in the presence of a known radical polymerization initiator such as a peroxide or azo compound, and diluting it with an organic solvent as necessary.

[0208] Water-based acrylic polyols can be produced by known methods such as solution polymerization of olefinic unsaturated compounds and conversion to an aqueous layer, or emulsion polymerization. In this case, water solubility or water dispersibility can be imparted by neutralizing the acidic portion of carboxylic acid-containing monomers such as acrylic acid and methacrylic acid, or sulfonic acid-containing monomers, with amines or ammonia.

[0209] [Hydroxyl value and acid value of polyhydric hydroxy compounds] The hydroxyl value of the polyvalent hydroxy compound contained in the resin composition of this embodiment is preferably 5 mg KOH / g or more and 300 mg KOH / g or less, more preferably 10 mg KOH / g or more and 280 mg KOH / g or less, and even more preferably 30 mg KOH / g or more and 250 mg KOH / g or less. By having the hydroxyl value of the polyvalent hydroxy compound within the above range, a resin film with superior physical properties such as tensile strength can be obtained. Specifically, by having the hydroxyl groups of the polyvalent hydroxy compound above the lower limit, the crosslinking density of the urethane due to the reaction with the polyisocyanate is increased, making it easier for the urethane bond to exhibit its function. On the other hand, by having the hydroxyl groups of the polyvalent hydroxy compound below the upper limit, the crosslinking density does not increase excessively, resulting in better mechanical properties of the resin film.

[0210] The hydroxyl value of a polyhydric hydroxy compound is measured, for example, by potentiometric titration and calculated as a value relative to the solid content in the polyhydric hydroxy compound.

[0211] [Glass transition temperature (Tg) of polyvalent hydroxy compounds] The glass transition temperature Tg of the polyhydroxy compound contained in the resin composition of the present embodiment is preferably 0°C or higher and 100°C or lower, more preferably 0°C or higher and 90°C or lower, further preferably 0°C or higher and 80°C or lower, and particularly preferably 5°C or higher and 70°C or lower. When the glass transition temperature of the polyhydroxy compound falls within the above range, a resin film having more excellent tensile strength can be obtained. The glass transition temperature of the polyhydroxy compound can be measured, for example, by the method described in the examples mentioned later.

[0212] [Weight average molecular weight Mw of polyhydroxy compound] The weight average molecular weight Mw of the polyhydroxy compound is 5.0×10 3 or more and 2.0×10 5 or less, preferably 5.0×10 3 or more and 1.5×10 5 or less, more preferably 5.0×10 3 or more and 1.0×10 5 or less, and even more preferably within this range. When the weight average molecular weight Mw of the polyhydroxy compound falls within the above range, a resin film having more excellent various physical properties such as tensile strength can be obtained. The weight average molecular weight Mw of the polyhydroxy compound can be measured, for example, by the method described in the examples mentioned later.

[0213] [NCO / OH] The molar equivalent ratio of isocyanate groups of the blocked polyisocyanate composition to hydroxyl groups of the polyhydroxy compound contained in the resin composition of the present embodiment (NCO / OH) is determined depending on the required physical properties of the resin film, and is usually 0.01 or more and 22.5 or less.

[0214] [Content of blocked polyisocyanate composition] In the resin composition of this embodiment, the content of blocked polyisocyanate is sufficient as long as the molar equivalent ratio of the isocyanate groups of the blocked polyisocyanate to the hydroxyl groups of the polyhydric hydroxy compound is within the above range. For example, it is preferable that the content be 1 to 200 parts by mass, more preferably 5 to 180 parts by mass, and even more preferably 10 to 150 parts by mass per 100 parts by mass of the polyhydric hydroxy compound. By having a blocked polyisocyanate content within the above range, a resin film with superior physical properties such as tensile strength can be obtained. The content of blocked polyisocyanate can be calculated, for example, from the blending amount, or it can be calculated by identification and quantification using nuclear magnetic resonance (NMR) and gas chromatography / mass spectrometry (GC / MS).

[0215] <<Other additives>> The resin composition of this embodiment may further contain other additives. Other additives include, for example, curing agents, curing catalysts, solvents, pigments (extender pigments, coloring pigments, metallic pigments, etc.) that can react with crosslinkable functional groups in polyvalent hydroxy compounds, UV absorbers, light stabilizers, radical stabilizers, anti-yellowing agents to suppress discoloration during the baking process, coating modifiers, flow modifiers, pigment dispersants, defoamers, thickeners, and film-forming aids.

[0216] Examples of the curing agent include melamine resin, urea resin, epoxy group-containing compound or resin, carboxyl group-containing compound or resin, acid anhydride, alkoxysilane group-containing compound or resin, hydrazide compound, and the like.

[0217] The curing catalyst may be a basic compound or a Lewis acid compound. Examples of the basic compound include metal hydroxides, metal alkoxides, metal carboxylates, metal acetyl acetylates, hydroxides of onium salts, onium carboxylates, halides of onium salts, metal salts of active methylene compounds, onium salts of active methylene compounds, aminosilanes, amines, phosphines, and the like. Ammonium salts, phosphonium salts, or sulfonium salts are preferred as the onium salt. Examples of the Lewis acid compounds include organotin compounds, organozinc compounds, organotitanium compounds, and organozirconium compounds.

[0218] Examples of the aforementioned solvent include those exemplified in the above-mentioned block polyisocyanate composition.

[0219] Furthermore, known pigments (extender pigments, coloring pigments, metallic pigments, etc.), ultraviolet absorbers, light stabilizers, radical stabilizers, anti-yellowing agents to suppress discoloration during the baking process, surface modifiers, flow modifiers, pigment dispersants, defoamers, thickeners, and film-forming aids can be appropriately selected and used.

[0220] ≪Method for manufacturing resin compositions≫ The resin composition of this embodiment can be used as either a solvent-based or water-based composition, but it is preferably used as a water-based resin composition.

[0221] When producing an aqueous resin composition, first, a polyvalent hydroxy compound or its aqueous dispersion or aqueous solution is added, as needed, to which additives such as a curing agent, curing catalyst, solvent, pigments (extender pigments, coloring pigments, metallic pigments, etc.), ultraviolet absorber, light stabilizer, radical stabilizer, anti-yellowing agent to suppress discoloration during the baking process, coating surface modifier, flow modifier, pigment dispersant, defoamer, thickener, and film-forming aid are added. Next, the above-mentioned block polyisocyanate composition or its aqueous dispersion is added as a curing agent, and water or solvent is further added as needed to adjust the viscosity. Finally, the aqueous resin composition can be obtained by forced stirring with a stirring device.

[0222] When manufacturing a solvent-based resin composition, first, a polyvalent hydroxy compound or its solvent dilution is mixed with additives such as a curing agent, curing catalyst, solvent, pigments (extender pigments, coloring pigments, metallic pigments, etc.) that can react with the crosslinkable functional group in the polyvalent hydroxy compound, as needed, UV absorbers, light stabilizers, radical stabilizers, anti-yellowing agents to suppress discoloration during the baking process, coating surface modifiers, flow modifiers, pigment dispersants, defoamers, thickeners, and film-forming aids. Next, the above-mentioned block polyisocyanate composition is added as a curing agent, and if necessary, a solvent is further added to adjust the viscosity. Finally, the mixture is stirred by hand or using a stirring device such as a mixer to obtain the solvent-based resin composition.

[0223] <Resin film> This embodiment is a resin film obtained by curing the resin composition of this embodiment. The resin film of this embodiment has excellent hardness and strength.

[0224] The resin film of this embodiment is obtained by coating the above-mentioned resin composition onto a substrate using known methods such as roll coating, curtain flow coating, spray coating, bell coating, and electrostatic coating, and then curing it by heating.

[0225] From the viewpoint of energy saving and the heat resistance of the substrate, the heating temperature is preferably between approximately 70°C and approximately 120°C, more preferably between approximately 70°C and approximately 110°C, and even more preferably between approximately 75°C and approximately 100°C. From the viewpoint of energy saving and the heat resistance of the base material, the heating time is preferably about 1 minute to about 60 minutes, and more preferably about 2 minutes to about 40 minutes.

[0226] The base material is not particularly limited and includes, for example, the exterior panels of automobile bodies such as passenger cars, trucks, motorcycles, and buses; automobile parts such as bumpers; the exterior panels of household electrical appliances such as mobile phones and audio equipment; and various films. Among these, the exterior panels of automobile bodies or automobile parts are preferred.

[0227] The material of the base material is not particularly limited and includes, for example, metal materials such as iron, aluminum, brass, copper, tinplate, stainless steel, galvanized steel, and zinc alloy (Zn-Al, Zn-Ni, Zn-Fe, etc.) plated steel; resins such as polyethylene resin, polypropylene resin, acrylonitrile-butadiene-styrene (ABS) resin, polyamide resin, acrylic resin, vinylidene chloride resin, polycarbonate resin, polyurethane resin, epoxy resin, and various FRP plastic materials; inorganic materials such as glass, cement, and concrete; wood; and fibrous materials such as paper and cloth. Among these, metal materials or plastic materials are preferred.

[0228] The substrate may be the surface of the metal material described above, or the metal surface of a car body or the like molded from the metal material, that has been subjected to surface treatment such as phosphate treatment, chromate treatment, or composite oxide treatment, and may also have a coating film formed thereon. The substrate on which the coating film is formed may be one on which a surface treatment has been applied as necessary, and an undercoat coating film has been formed thereon, for example, a car body on which an undercoat coating film has been formed by electrodeposition paint. The substrate may be the surface of the plastic material described above, or the plastic surface of an automobile part or the like molded from the metal material, that has been subjected to a desired surface treatment. Furthermore, the substrate may be a combination of plastic material and metal material.

[0229] Because the resin film of this embodiment exhibits excellent low-temperature curing properties, it is suitable for use in products in various fields where energy conservation is required, and as a coating for materials with low heat resistance.

[0230] <Laminate> This embodiment is a laminate in which one or more layers of the resin film of this embodiment are laminated on a substrate. The thickness of each layer constituting the resin film is 1 μm to 50 μm. The laminate of this embodiment has excellent hardness and strength due to the inclusion of the above-mentioned resin film.

[0231] The laminate of this embodiment may contain two or more layers of the above-mentioned resin film having the same composition, or it may contain two or more layers of the above-mentioned resin film having different compositions. Furthermore, the same materials as those exemplified in the "resin film" section above can be used as the base material.

[0232] The laminate of this embodiment is obtained by applying the above resin composition to a substrate using known methods such as roll coating, curtain flow coating, spray coating, bell coating, and electrostatic coating, and then heating and curing each layer, or by heating and curing all layers together after coating.

[0233] The laminate of this embodiment may include, in addition to the resin film, layers made of other known components, such as a primer layer, an adhesive layer, or a decorative layer. [Examples]

[0234] The embodiment will be described in more detail below based on examples and comparative examples, but the embodiment is not limited in any way by the following examples.

[0235] <Test Items> The physical properties of the block polyisocyanate compositions obtained in the examples and comparative examples were measured and evaluated according to the methods described below.

[0236] [Physical Properties 1] (Isocyanate group (NCO) content) To measure the NCO content of polyisocyanates, polyisocyanates before blocking with a blocking agent were used as the sample. First, 2 g to 3 g of the sample was accurately weighed into a flask (Wg). Next, 20 mL of toluene was added and the sample was dissolved. Then, 20 mL of a 2 N di-n-butylamine toluene solution was added and mixed, and the mixture was left at room temperature for 15 minutes. Next, 70 mL of isopropyl alcohol was added and mixed. This solution was then titrated with a 1 N hydrochloric acid solution (factor F) on an indicator. The obtained titration value was defined as V2 mL. Next, the titration value obtained without the polyisocyanate sample was defined as V1 mL. Then, the isocyanate group (NCO) content (mass%) of the polyisocyanate was calculated using the following formula. Isocyanate group (NCO) content (mass%) = (V1-V2) × F × 42 / (W × 1000) × 100

[0237] [Physical Properties 2] (Number-average molecular weight and weight-average molecular weight) The number-average molecular weight and weight-average molecular weight are those measured using gel permeation chromatography (GPC) with the following apparatus, based on polystyrene. To measure the number-average molecular weight of polyisocyanates, polyisocyanates were used as the sample before blocking with a blocking agent. For weight-average molecular weight, the block polyisocyanate composition or polyvalent hydroxy compound was used directly as the measurement sample. The measurement conditions are shown below.

[0238] (Measurement conditions) Equipment: HLC-802A, manufactured by Tosoh Corporation Column: Tosoh Corporation, G1000HXL x 1 G2000HXL x 1 G3000HXL x 1 Carrier: Tetrahydrofuran Detection method: Differential refractometer

[0239] [Physical Properties 3] (Average number of isocyanate groups) The average number of isocyanate groups (average NCO count) of the polyisocyanate was determined by the following formula. In the formula, "Mn" is the number-average molecular weight of the polyisocyanate before blocking with the blocking agent, and the value measured in "Physical Properties 2" above was used. "NCO content" is the isocyanate group content of the polyisocyanate measured before blocking with the blocking agent, and the value calculated in "Physical Properties 1" above was used. Average number of isocyanate groups = (Mn × NCO content × 0.01) / 42

[0240] [Physical Properties 4] (Solid content of the blocked polyisocyanate composition) The solid content of the blocked polyisocyanate composition was determined as follows: First, an aluminum dish with a base diameter of 38 mm was accurately weighed. Next, approximately 1 g of the block polyisocyanate composition produced in the examples and comparative examples was placed on the aluminum dish and weighed again (W1). Next, the block polyisocyanate composition was adjusted to a uniform thickness. Next, the block polyisocyanate composition on the aluminum dish was held in an oven at 105°C for 1 hour. After the aluminum dish had returned to room temperature, the block polyisocyanate composition remaining on the aluminum dish was accurately weighed (W2). Next, the solid content (mass%) of the block polyisocyanate composition was calculated using the following formula. Solid content (mass%) of the block polyisocyanate composition = W2 / W1 × 100

[0241] [Physical Properties 5] (moles of constituent units (I-1), (I-2), and (I-3)) The molar percentages of constituent units (I-1), (I-2), and (I-3) in constituent unit (I) of the blocked polyisocyanate composition were calculated using the method shown below. Specifically, using the JEOL-ECZ500(SC) (product name) manufactured by JEOL, 13By measuring with 1C-NMR, the total molar amount of constituent unit (I) (including constituent units (I-1), (I-2), and (I-3)) and the molar amounts of constituent units (I-1), (I-2), and (I-3) were calculated, and their molar percentages were determined.

[0242] (Measurement conditions) Device: JEOL “JEOL-ECZ500(SC)” (product name) Solvent: Deuterated chloroform Total number of times: 5120 Sample concentration: 50 wt / vol% Chemical shift standard: Deuterated chloroform was set at 77.0 ppm.

[0243] [Physical Properties 6] (moles of constituent unit (I-2-1) within constituent unit (I-2)) The molar percentage of constituent unit (I-2-1) in constituent unit (I-2) is obtained by evaporating the block polyisocyanate composition at a temperature of 50°C or lower using an evaporator to remove the solvent and other components, and then drying under reduced pressure. 13 The amount was measured by 13C-NMR and the mole percentage was calculated.

[0244] (Measurement conditions) Device: JEOL “JEOL-ECZ500(SC)” (product name) Solvent: Deuterated chloroform Total number of times: 5120 Sample concentration: 50 wt / vol% Chemical shift standard: Deuterated chloroform was set at 77.0 ppm.

[0245] [Physical Properties 7] (mol% of constituent unit (I-3-1) in constituent unit (I-3)) The molar percentage of constituent unit (I-3-1) in constituent unit (I-3) is obtained by evaporating the block polyisocyanate composition at a temperature of 50°C or lower to remove the solvent and other components, and then drying under reduced pressure. 13 The amount was measured by 13C-NMR and the mole percentage was calculated.

[0246] (Measurement conditions) Device: JEOL “JEOL-ECZ500(SC)” (product name) Solvent: Deuterated chloroform Total number of times: 5120 Sample concentration: 50 wt / vol% Chemical shift standard: Deuterated chloroform was set at 77.0 ppm.

[0247] [Physical Properties 8] (Mass ratio of blocked polyisocyanate / polar solvent) The mass amount of polar solvent in the blocked polyisocyanate composition was quantified by gas chromatography. The mass ratio of block polyisocyanate to polar solvent was calculated from the quantified amount of polar solvent and the solid content of block polyisocyanate.

[0248] Equipment: SHIMADZU GC-2014 Column: Agilent J&W DB-1 (L30m, I.D 0.25mm, Film 1.00um) Carrier gas: Helium Detector: FID Inlet temperature: 100℃ Detector temperature: 220℃ Oven temperature: 40°C (hold for 5 minutes) → (increase temperature by 10°C / minute) → 150°C (hold for 5 minutes) Injection volume: 0.3μL

[0249] [Rating 1] (High-temperature stability of blocked polyisocyanate compositions) The blocked polyisocyanate compositions were stored at 50°C and 60°C for one week, and their appearance was visually inspected. The stability of the blocked polyisocyanate compositions was evaluated according to the following evaluation criteria.

[0250] ◎: No change observed when stored at 50℃ or 60℃. ○: No change when stored at 50°C; precipitates form after 2-7 days of storage at 60°C. △: No change when stored at 50°C, but precipitates formed after 1 day of storage at 60°C. ×: Precipitation occurs at both 50℃ and 60℃.

[0251] [Rating 2] (Low-temperature stability of blocked polyisocyanate compositions) The blocked polyisocyanate composition was stored at -10°C for one week. After storage, it was cured at 23°C for two days, and then its appearance was visually inspected. The stability of the blocked polyisocyanate composition was evaluated according to the following evaluation criteria.

[0252] ○: No change before and after storage (liquid state maintained) △: Liquid, but contains some gel-like substances. ×: The entire thing turns into a gel-like state.

[0253] [Preparation of aqueous resin compositions] A water-based acrylic polyol (manufactured by Nuplex, "Setaqua® 6515" (trade name), OH (mol%) (on solids) = 3.3, Acid value (mgKOH / g) = 9.9, solids content 45% by mass) and each block polyisocyanate composition were blended in a ratio of isocyanate groups to hydroxyl groups (isocyanate groups / hydroxyl groups) of 0.80. Deionized water was then added, and a small amount of dimethylaminoethanol was added to prepare the solution to a pH of approximately 8.0 to 8.5 and a solids content of 45% by mass. Next, the solution was stirred at 1000 rpm for 15 minutes using a homodisper, and after degassing, a water-based resin composition was obtained.

[0254] [Rating 3] (Low temperature curing) The obtained resin composition was coated onto a polypropylene (PP) plate to a dry film thickness of 40 μm, and then heated and dried at 80°C for 30 minutes to obtain a resin film. The obtained resin film was stored at room temperature (23°C) for one week, and the gel fraction was measured. The gel fraction was determined as the percentage (mass%) of the undissolved portion mass of the resin film after immersion in acetone at 23°C for 24 hours, divided by the mass before immersion. The low-temperature curing properties were evaluated from the obtained gel fraction according to the following evaluation criteria.

[0255] (Evaluation Criteria) ○: Gel fraction of 85% by mass or more △: Gel fraction 80% by mass or more, less than 85% by mass ×: Gel fraction less than 80% by mass

[0256] [Rating 4] (Storage stability of water-based paint compositions) 20 g of the obtained aqueous resin composition was stored at 40°C for 3 days, and its viscosity was measured before and after storage. The viscosity change rate (viscosity after storage / viscosity before storage × 100) was evaluated according to the following evaluation criteria.

[0257] (Evaluation Criteria) ○: Less than 50% △: 50% or more ×: Gelation

[0258] <Synthesis of polyisocyanates> [Synthesis Example 1] (Synthesis of polyisocyanate P-1) In a four-necked flask equipped with a thermometer, stirring blades, and reflux condenser, 100 parts by mass of HDI and 5.2 parts by mass of polyester polyol derived from a trihydric alcohol and ε-caprolactone (Daicel Chemicals, "Praxel 303" (trade name), average number of functional groups: 3, number average molecular weight 300) were charged under a nitrogen stream. The reactor temperature was maintained at 88°C for 1 hour under stirring to carry out the urethane reaction. After that, the reactor temperature was maintained at 62°C, and the isocyanurate catalyst tetramethylammonium capriate was added. When the yield reached 51% by mass, phosphoric acid was added to stop the reaction. After filtering the reaction solution, unreacted HDI was removed using a thin-film evaporator to obtain isocyanurate-type polyisocyanate (hereinafter sometimes referred to as "polyisocyanate P-1"). The obtained polyisocyanate P-1 had an NCO content of 18.8% by mass, a number-average molecular weight of 1180, and an average number of isocyanate groups of 5.3.

[0259] [Synthesis Example 2] (Synthesis of polyisocyanate P-2) In a four-necked flask equipped with a thermometer, stirring blades, and reflux condenser, 100 parts by mass of polyisocyanate P-1 obtained in Synthesis Example 1, 20.3 parts by mass of dipropylene glycol dimethyl ether (DPDM), 15 parts by mass of methoxypolyethylene glycol (MPG-081, ethylene oxide repeating units: 15, manufactured by Nippon Emulsifier Co., Ltd.) (an amount equivalent to 5 mol% relative to 100 mol% of isocyanate groups in polyisocyanate P2-1), 0.01 parts by mass of dibutyl phosphoric acid (DBP, manufactured by Johoku Chemical Industry Co., Ltd.), and dipropylene glycol dimethyl ether (DPDM) were mixed under a nitrogen stream and stirred at 120°C for 2 hours to obtain polyisocyanate P-2. The obtained polyisocyanate P-2 had an NCO content of 13.2% by mass and an average number of isocyanate groups of 5.0.

[0260] <Production of Block Polyisocyanate Compositions> [Example 1] (Preparation of Block Polyisocyanate Composition BL-1) In a four-necked flask equipped with a thermometer, stirring blade, and reflux condenser, 100 parts by mass of polyisocyanate P-2 obtained in Synthesis Example 2, 10.1 parts by mass of diethyl malonate (20 mol% relative to 100 mol% of NCO groups), 3.0 parts by mass of diisopropyl malonate (5 mol% relative to 100 mol% of NCO groups), and 52.3 parts by mass of ditert-butyl malonate (77 mol% relative to 100 mol% of NCO groups) were charged under a nitrogen stream. Dipropylene glycol dimethyl ether (DPDM) was then added to prepare a solution with a solid content of 60% by mass. Next, while stirring, 0.9 parts by mass of methanol solution containing sodium methylate (28% by mass relative to the total mass of the solution) was added dropwise, and the external bath was adjusted to a solution temperature of 55°C. The blocking reaction was carried out at 55°C for 5 hours. After the reaction, 1.0 part by mass of dibutyl phosphate was added, and the mixture was stirred for 10 minutes to obtain block polyisocyanate composition BL-a1 with a solid content of 60% by mass.

[0261] [Example 2] (Preparation of Block Polyisocyanate Composition BL-a2) In a four-necked flask equipped with a thermometer, stirring blades, and reflux condenser, 100 parts by mass of polyisocyanate P-2 obtained in Synthesis Example 2 and 51.3 parts by mass of diethyl malonate (102 mol% relative to 100 mol% of NCO groups) were charged under a nitrogen stream. Dipropylene glycol dimethyl ether (DPDM) was then added to prepare a solution with a solid content of 60% by mass. Next, while stirring, 0.9 parts by mass of methanol solution containing sodium methylate (28% by mass relative to the total mass of the solution) was added dropwise, and the external bath was adjusted to a solution temperature of 55°C. The blocking reaction was carried out at 55°C for 5 hours. After the reaction, 1.0 part by mass of dibutyl phosphoric acid was added, and the mixture was stirred for 10 minutes to obtain a blocked polyisocyanate composition intermediate with a solid content of 60% by mass. Subsequently, 113.0 parts by mass of 2-methyl-2-butanol (400 mol% relative to the blocked isocyanate group) was added, and the mixture was reacted at 100°C for 5 hours while removing the generated ethanol by distillation under atmospheric pressure. Then, ethanol and 2-methyl-2-butanol were further removed by distillation at 60°C under reduced pressure (50 kPa). Next, 1.0 part by mass of isopropyl alcohol was added, and the mixture was stirred at 80°C for 2 hours. Finally, dipropylene glycol dimethyl ether (DPDM) was added to adjust the solid content to 60% by mass, obtaining the blocked polyisocyanate composition BL-a2.

[0262] [Example 3] (Preparation of Block Polyisocyanate Composition BL-a3) In a four-necked flask equipped with a thermometer, stirring blades, and reflux condenser, 100 parts by mass of polyisocyanate P-2 obtained in Synthesis Example 2 and 51.3 parts by mass of diethyl malonate (102 mol% relative to 100 mol% of NCO groups) were charged under a nitrogen stream. Dipropylene glycol dimethyl ether (DPDM) was then added to prepare a solution with a solid content of 60% by mass. Next, while stirring, 0.9 parts by mass of methanol solution containing sodium methylate (28% by mass relative to the total mass of the solution) was added dropwise, and the external bath was adjusted to a solution temperature of 55°C. The blocking reaction was carried out at 55°C for 5 hours. After the reaction, 1.0 part by mass of dibutyl phosphoric acid was added, and the mixture was stirred for 10 minutes to obtain a blocked polyisocyanate composition intermediate with a solid content of 60% by mass. Subsequently, 113.0 parts by mass of 2-methyl-2-butanol (400 mol% relative to the blocked isocyanate group) was added, and the mixture was reacted at 100°C for 10 hours while removing the generated ethanol by distillation under atmospheric pressure. Then, ethanol and 2-methyl-2-butanol were further removed by distillation at 60°C under reduced pressure (50 kPa). After that, 1.0 part by mass of isopropyl alcohol was added, and the mixture was stirred at 80°C for 2 hours. Finally, dipropylene glycol dimethyl ether (DPDM) was added to adjust the solid content to 60% by mass, obtaining the blocked polyisocyanate composition BL-a3.

[0263] [Example 4] (Preparation of Block Polyisocyanate Composition BL-a4) In a four-necked flask equipped with a thermometer, stirring blades, and reflux condenser, 100 parts by mass of polyisocyanate P-2 obtained in Synthesis Example 2 and 51.3 parts by mass of diethyl malonate (102 mol% relative to 100 mol% of NCO groups) were charged under a nitrogen stream. Dipropylene glycol dimethyl ether (DPDM) was then added to prepare a solution with a solid content of 60% by mass. Next, while stirring, 0.9 parts by mass of methanol solution containing sodium methylate (28% by mass relative to the total mass of the solution) was added dropwise, and the external bath was adjusted to a solution temperature of 55°C. The blocking reaction was carried out at 55°C for 5 hours. After the reaction, 1.0 part by mass of dibutyl phosphoric acid was added, and the mixture was stirred for 10 minutes to obtain a blocked polyisocyanate composition intermediate with a solid content of 60% by mass. Subsequently, 113.0 parts by mass of 2-methyl-2-butanol (400 mol% relative to the blocked isocyanate group) was added, and the mixture was reacted at 100°C for 5 hours while removing the generated ethanol by distillation under atmospheric pressure. Then, the ethanol and 2-methyl-2-butanol were further removed by distillation at 60°C under reduced pressure (50 kPa). Next, 1.0 part by mass of isopropyl alcohol was added, and the mixture was stirred at 80°C for 2 hours. Finally, 2-methyl-2-butanol was added in a ratio of 92 / 8 between the blocked polyisocyanate and 2-methyl-2-butanol, and dipropylene glycol dimethyl ether (DPDM) was added to adjust the solid content to 60% by mass, thereby obtaining the blocked polyisocyanate composition BL-a4.

[0264] [Example 5] (Preparation of Block Polyisocyanate Composition BL-a5) In a four-necked flask equipped with a thermometer, stirring blades, and reflux condenser, 100 parts by mass of polyisocyanate P-2 obtained in Synthesis Example 2 and 51.3 parts by mass of diethyl malonate (102 mol% relative to 100 mol% of NCO groups) were charged under a nitrogen stream. Dipropylene glycol dimethyl ether (DPDM) was then added to prepare a solution with a solid content of 60% by mass. Next, while stirring, 0.9 parts by mass of methanol solution containing sodium methylate (28% by mass relative to the total mass of the solution) was added dropwise, and the external bath was adjusted to a solution temperature of 55°C. The blocking reaction was carried out at 55°C for 5 hours. After the reaction, 1.0 part by mass of dibutyl phosphoric acid was added, and the mixture was stirred for 10 minutes to obtain a blocked polyisocyanate composition intermediate with a solid content of 60% by mass. Subsequently, 113.0 parts by mass of 2-methyl-2-butanol (400 mol% relative to the blocked isocyanate group) was added, and the mixture was reacted at 100°C for 5 hours while removing the generated ethanol by distillation under atmospheric pressure. Then, ethanol and 2-methyl-2-butanol were further removed by distillation at 60°C under reduced pressure (50 kPa). Next, 1.0 part by mass of isopropyl alcohol was added, and the mixture was stirred at 80°C for 2 hours. Finally, dimethylformamide was added in a ratio of 92 / 8 between the blocked polyisocyanate and dimethylformamide, and then dipropylene glycol dimethyl ether (DPDM) was added to adjust the solid content to 60% by mass, obtaining the blocked polyisocyanate composition BL-a5.

[0265] [Example 6] (Preparation of block polyisocyanate composition BL-a6) In a four-necked flask equipped with a thermometer, stirring blades, and reflux condenser, 100 parts by mass of polyisocyanate P-2 obtained in Synthesis Example 2 and 51.3 parts by mass of diethyl malonate (102 mol% relative to 100 mol% of NCO groups) were charged under a nitrogen stream. Dipropylene glycol dimethyl ether (DPDM) was then added to prepare a mixture with a solid content of 60% by mass. Next, while stirring, 0.9 parts by mass of methanol solution containing sodium methylate (28% by mass relative to the total mass of the solution) was added dropwise. The external bath was then adjusted to a solution temperature of 55°C, and the blocking reaction was carried out at 55°C for 5 hours to obtain a blocked polyisocyanate composition intermediate with a solid content of 60% by mass. Subsequently, 113.0 parts by mass of 2-methyl-2-butanol (400 mol% relative to the blocked isocyanate groups) was added, and the reaction was carried out at 100°C for 5 hours while removing the generated ethanol by distillation under atmospheric pressure. Subsequently, ethanol and 2-methyl-2-butanol were further removed by distillation under reduced pressure (50 kPa) at 60°C. Then, 1.0 part by mass of isopropyl alcohol was added, and the mixture was stirred at 80°C for 2 hours. Finally, dipropylene glycol dimethyl ether (DPDM) was added to adjust the solid content to 60% by mass, yielding block polyisocyanate composition BL-a6.

[0266] [Example 7] (Preparation of Block Polyisocyanate Composition BL-a7) In a four-necked flask equipped with a thermometer, stirring blades, and reflux condenser, 100 parts by mass of polyisocyanate P-2 obtained in Synthesis Example 2 and 51.3 parts by mass of diethyl malonate (102 mol% relative to 100 mol% of NCO groups) were charged under a nitrogen stream. Dipropylene glycol dimethyl ether (DPDM) was then added to prepare a solution with a solid content of 60% by mass. Next, while stirring, 1.6 parts by mass of methanol solution containing sodium methylate (28% by mass relative to the total mass of the solution) was added dropwise, and the external bath was adjusted to a solution temperature of 55°C. The blocking reaction was carried out at 55°C for 5 hours. After the reaction, 1.8 parts by mass of dibutyl phosphoric acid was added, and the mixture was stirred for 10 minutes to obtain a blocked polyisocyanate composition intermediate with a solid content of 60% by mass. Subsequently, 113.0 parts by mass of 2-methyl-2-butanol (400 mol% relative to the blocked isocyanate group) was added, and the mixture was reacted at 100°C for 5 hours while removing the generated ethanol by distillation under atmospheric pressure. Then, ethanol and 2-methyl-2-butanol were further removed by distillation at 60°C under reduced pressure (50 kPa). After that, 1.0 part by mass of isopropyl alcohol was added, and the mixture was stirred at 80°C for 2 hours. Finally, dipropylene glycol dimethyl ether (DPDM) was added to adjust the solid content to 60% by mass, obtaining the blocked polyisocyanate composition BL-a7.

[0267] [Example 8] (Production of Block Polyisocyanate Composition BL-8) In a four-necked flask equipped with a thermometer, stirring blades, and reflux condenser, 100 parts by mass of polyisocyanate P-2 obtained in Synthesis Example 2, 10.1 parts by mass of diethyl malonate (20 mol% relative to 100 mol% of NCO groups), 3.0 parts by mass of diisopropyl malonate (5 mol% relative to 100 mol% of NCO groups), and 52.3 parts by mass of ditert-butyl malonate (77 mol% relative to 100 mol% of NCO groups) were charged under a nitrogen stream. Dipropylene glycol dimethyl ether (DPDM) was then added to prepare a solution with a solid content of 60% by mass. Next, while stirring, 0.9 parts by mass of methanol solution containing sodium methylate (28% by mass relative to the total mass of the solution) was added dropwise, and the external bath was adjusted to a solution temperature of 55°C. The blocking reaction was carried out at 55°C for 5 hours. After the reaction, 1.0 part by mass of dibutyl phosphoric acid was added and stirred for 10 minutes. Finally, dimethylformamide was added in a ratio of 92 / 8 between the block polyisocyanate and dimethylformamide to obtain block polyisocyanate composition BL-a8 with a solid content of 60% by mass.

[0268] [Comparative Example 1] (Preparation of Block Polyisocyanate Composition BL-b1) In a four-necked flask equipped with a thermometer, stirring blades, and reflux condenser, 100 parts by mass of polyisocyanate P-2 obtained in Synthesis Example 2 and 51.3 parts by mass of diethyl malonate (102 mol% relative to 100 mol% of NCO groups) were charged under a nitrogen stream. Dipropylene glycol dimethyl ether (DPDM) was then added to prepare a solution with a solid content of 60% by mass. Next, while stirring, 0.9 parts by mass of methanol solution containing sodium methylate (28% by mass relative to the total mass of the solution) was added dropwise, and the external bath was adjusted to a solution temperature of 55°C. The blocking reaction was carried out at 55°C for 5 hours. After the reaction, 1.0 part by mass of dibutyl phosphoric acid was added, and the mixture was stirred for 10 minutes to obtain a blocked polyisocyanate composition intermediate with a solid content of 60% by mass. Subsequently, 113.0 parts by mass of 2-methyl-2-butanol (400 mol% relative to the blocked isocyanate group) was added, and the mixture was reacted at 100°C for 5 hours while removing the generated ethanol by distillation under atmospheric pressure. Then, the ethanol and 2-methyl-2-butanol were further removed by distillation at 60°C under reduced pressure (50 kPa). Finally, dipropylene glycol dimethyl ether (DPDM) was added to adjust the solid content to 60% by mass, obtaining the blocked polyisocyanate composition BL-b1.

[0269] [Comparative Example 2] (Preparation of Block Polyisocyanate Composition BL-b2) In a four-necked flask equipped with a thermometer, stirring blades, and reflux condenser, 100 parts by mass of polyisocyanate P-2 obtained in Synthesis Example 2, 48.8 parts by mass of diethyl malonate (97 mol% relative to 100 mol% of NCO groups), and 3.0 parts by mass of diisopropyl malonate (5 mol% relative to 100 mol% of NCO groups) were charged under a nitrogen stream. Dipropylene glycol dimethyl ether (DPDM) was then added to prepare a solution with a solid content of 60% by mass. Next, while stirring, 0.9 parts by mass of methanol solution containing sodium methylate (28% by mass relative to the total mass of the solution) was added dropwise, and the external bath was adjusted to a solution temperature of 55°C. The blocking reaction was carried out at 55°C for 5 hours. After the reaction, 1.0 part by mass of dibutyl phosphate was added and stirred for 10 minutes. Finally, dimethylformamide was added in a ratio of 92 / 8 between the block polyisocyanate and dimethylformamide to obtain block polyisocyanate composition BL-b2 with a solid content of 60% by mass.

[0270] The following table shows the measurement results of the physical properties of each block polyisocyanate composition obtained in the examples and comparative examples, as well as the evaluation results using the method described above.

[0271] [Table 1]

[0272] The details of each constituent unit (I-1-1), (I-2-1) to (I-2-2), and (I-3-1) to (I-3-2) in Table 1 are as follows. Constituent unit (I-1-1): In general formula (I), R 11 is a methyl group, R 12 is a hydrogen atom, R 13 is a hydrogen atom, R 14 is a methyl group, R 15 is a hydrogen atom, R 16 A structure in which the atoms are hydrogen atoms. Constituent unit (I-2-1): In general formula (I), R 11 is a methyl group, R 12 is a hydrogen atom, R 13 is a hydrogen atom, R 14 is a methyl group, R15 is a methyl group, R 16 A structure in which the atoms are hydrogen atoms. Constituent unit (I-2-2): In general formula (I), R 11 is a methyl group, R 12 is a methyl group, R 13 is a hydrogen atom, R 14 is a methyl group, R 15 is a methyl group, R 16 A structure in which the atoms are hydrogen atoms. Constituent unit (I-3-1): The constituent unit (I-3-1) can take on the following two types of structures. In general formula (I), R 11 is a methyl group, R 12 is a methyl group, R 13 is a methyl group, R 14 is a methyl group, R 15 is a methyl group, R 16 A structure in which is a methyl group. In general formula (I), R 11 is an ethyl group, R 12 is a methyl group, R 13 is a methyl group, R 14 is an ethyl group, R 15 is a methyl group, R 16 A structure in which is a methyl group. Constituent unit (I-3-2): The constituent unit (I-3-2) can take on the following two types of structures. In general formula (I), R 11 is an ethyl group, R 12 is a methyl group, R 13 is a methyl group, R 14 is a methyl group, R 15 is a hydrogen atom, R 16 A structure in which the atoms are hydrogen atoms. • In general formula (I), R 11 is an ethyl group, R 12 is a methyl group, R 13 is a methyl group, R 14 is a methyl group, R 15 is a methyl group, R 16 A structure in which the atoms are hydrogen atoms.

[0273] Table 2 lists the constituent units (I-1-1), (I-2-1)~(I-2-2), and (I-3-1)~(I-3-2) that were specifically used in Examples 1~8 and Comparative Examples 1~2. In Table 2, R 11 ~R 16 R in the above general formula (I) is 11 ~R 16 It means...

[0274] [Table 2]

Claims

1. A block polyisocyanate composition comprising a block polyisocyanate, The aforementioned blocked polyisocyanate is derived from a polyisocyanate and one or more blocking agents. The block polyisocyanate composition comprises a structural unit (I-1), a structural unit (I-2), and a structural unit (I-3) within the molecule. The aforementioned constituent unit (I-1) is R in the following general formula (I). １２ , R １３ , R １５ and R １６ However, the constituent unit is the hydrogen atom. Said structural unit (I-2) is represented by the following general formula (I), wherein R １１ , R １２ and R １３ at least one of which is a hydrogen atom, and R １４ and R １５ is an alkyl group which may comprise one or more substituents selected from the group consisting of hydroxy groups and amino groups, and R １６ is a structural unit in which R is a hydrogen atom. The aforementioned constituent unit (I-3) is R in the following general formula (I). １１ , R １２ and R １３ Each of these is an alkyl group which may contain one or more substituents selected from the group consisting of hydroxyl groups and amino groups, and R １１ , R １２ and R １３ It is a constituent unit whose total number of carbon atoms is between 3 and 20. The total amount of the constituent units represented by the following general formula (I) contains 1 mol% to 75 mol% of the constituent unit (I-1), 0.05 mol% to 10 mol% of the constituent unit (I-2), and 20 mol% to 98 mol% of the constituent unit (I-3). 【Chemistry 1】 (In general formula (I), R １１ , R １２ , R １３ , R １４ , R １５ and R １６ Each of these is an alkyl group that may independently contain a hydrogen atom or one or more substituents selected from the group consisting of a hydroxyl group and an amino group, and the wavy lines represent bonding bonds.

2. Within the aforementioned structural unit (I-2), R １２ and R １３ However, it is a hydrogen atom, and R １４ and R １５ R is an alkyl group which may contain one or more substituents selected from the group consisting of hydroxyl groups and amino groups, １６ The block polyisocyanate composition according to claim 1, wherein the constituent unit (I-2-1) is a hydrogen atom.

3. R of the aforementioned structural unit (I-3) １１ , R １２ and R １３ The block polyisocyanate composition according to claim 1, wherein the total number of carbon atoms is 4 or more and 20 or less.

4. The blocked polyisocyanate composition according to claim 1 or 2, wherein a portion of the isocyanate groups of the polyisocyanate are modified with a nonionic compound.

5. The block polyisocyanate composition according to claim 1 or 2, comprising a polar solvent, wherein the mass ratio of the block polyisocyanate to the polar solvent is 99 / 1 to 1 / 99.

6. A resin composition comprising the block polyisocyanate composition according to claim 1 or 2 and a polyvalent hydroxy compound.

7. A resin film obtained by curing the resin composition according to claim 6.

8. A laminate comprising one or more layers of the resin film described in claim 7 on a substrate, wherein the thickness of each layer constituting the laminate is 1 μm or more and 50 μm or less.

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