Carboxy group-containing imide-urethane resin and method for producing the same and resin composition

Abstract

To provide a carboxyl group-containing imide-urethane resin which has excellent flexibility, low water absorptivity, low dielectric properties and excellent compatibility with an epoxy resin, as well as good solubility in a low boiling point solvent.SOLUTION: There is provided a carboxyl group-containing imide-urethane resin which has a structural unit derived from a carboxy group-containing polyesterimide resin having a hydroxyl group at the terminal and a structural unit derived from a polyisocyanate (d) wherein the carboxy group-containing polyesterimide resin has a structural unit derived from a polyol (a), a structural unit derived from a polyamine (b) and a structural unit derived from a tetracarboxylic acid dianhydride (c) and the polyamine (b) is a dimer diamine.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a carboxyl group-containing imide urethane resin, a method for producing the same, and a resin composition. [Background technology]

[0002] Polyurethane resins are excellent in various physical properties such as abrasion resistance, flexibility, and adhesion, and are suitable for various processing methods. For this reason, polyurethane resins are widely used as binders for various coating agents, inks, paints, etc., and as constituent materials for various molded products including films and sheets. In particular, polyurethane resins used in fields such as vehicles and electronic materials are required to have excellent durability.

[0003] A method of introducing a carboxy group into a side chain is known as a method of controlling the function of a polyurethane resin. For example, an adhesive that combines a polyurethane resin having a carboxy group with an epoxy resin, which can form a cured product with improved properties such as heat resistance, has been proposed (Patent Document 1). Note that the properties required for a resin composition containing such a polyurethane resin having a carboxy group include flexibility, heat resistance, low-temperature drying properties, low water absorption, low dielectric properties, and compatibility with epoxy resins.

[0004] In addition, in order to increase the flexibility of polyurethane resins containing carboxyl groups, polyurethane resins having carboxyl groups have been proposed, which are obtained by using a carboxyl group-containing polyol, which is a reaction product of a tetracarboxylic dianhydride such as pyromellitic dianhydride (PMDA) and a polyol (Patent Document 2).Furthermore, in order to improve heat resistance, polyurethane resins into which imide bonds have been introduced have been proposed (Patent Document 3).

[0005] Also, in order to provide an adhesive composition with improved properties such as low dielectric properties, a polyimide urethane resin produced using a dimer diol has been proposed (Patent Document 4). Furthermore, an esterimide resin having a carboxy group obtained by reacting a dimer diamine, a polyol, and a tetracarboxylic dianhydride has been proposed as an imide resin with improved solubility in low boiling point solvents (Patent Document 5). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6499860 [Patent Document 2] JP 2019-1952 A [Patent Document 3] JP 2011-94037 A [Patent Document 4] Patent No. 7014296 [Patent Document 5] JP 2022-96061 A Summary of the Invention [Problem to be solved by the invention]

[0007] The polyurethane resin proposed in Patent Document 2 had good flexibility, but not necessarily good heat resistance. The polyurethane resin proposed in Patent Document 3 had good heat resistance, but not necessarily good flexibility and solubility in low boiling point solvents. By reducing the concentration of imide bonds, the solubility in low boiling point solvents was improved to a certain extent, but the heat resistance was easily reduced. The polyimide urethane resin proposed in Patent Document 4 had good low water absorption and low dielectric properties because it contained a highly hydrophobic structure derived from dimer diol. However, the flexibility and solubility in low boiling point solvents were not necessarily good, and the introduction sites of carboxyl groups were concentrated at the terminals, making it difficult to increase the crosslink density and heat resistance of the cured product.

[0008] The esterimide resin proposed in Patent Document 5 has good heat resistance, flexibility, and solubility in low-boiling solvents because it contains an imide structure derived from dimer diamine. However, it has low compatibility with the epoxy resin used as a curing agent, so the solution stability of the composition obtained by combining it with the epoxy resin is not necessarily good, and there are problems such as a tendency for poor curing to occur.

[0009] The present invention has been made in consideration of the problems associated with the conventional techniques, and an object of the present invention is to provide a carboxy group-containing imide urethane resin which has excellent flexibility, low water absorption, low dielectric properties and compatibility with epoxy resins and can be well dissolved in low-boiling point solvents, as well as a method for producing the same.

[0010] Another object of the present invention is to provide a resin composition which is well compatible with an epoxy resin that acts as a curing agent, etc., and which is capable of forming a cured product such as a cured layer that is excellent in flexibility, low water absorption, heat resistance, and low dielectric properties. [Means for solving the problem]

[0011] That is, according to the present invention, there is provided the following carboxy group-containing imide urethane resin. [1] A carboxyl-containing imide urethane resin having a structural unit derived from a carboxyl-containing polyesterimide resin having a hydroxyl group at its terminal and a structural unit derived from a polyisocyanate (d), the carboxyl-containing polyesterimide resin having a structural unit derived from a polyol (a), a structural unit derived from a polyamine (b), and a structural unit derived from a tetracarboxylic dianhydride (c), the polyamine (b) being a dimer diamine. [2] The carboxyl group-containing imide urethane resin according to [1] above, having a number average molecular weight of 2,000 to 100,000. [3] The carboxyl group-containing imide urethane resin according to [1] or [2] above, having an acid value of 5 to 100 mgKOH / g. [4] The carboxyl group-containing imide urethane resin according to any one of [1] to [3] above, having an imide bond concentration of 0.20 to 2.00 mmol / g. [5] The carboxyl group-containing imide urethane resin according to any one of [1] to [4] above, having a urethane bond concentration of 0.20 to 2.00 mmol / g.

[0012] According to the present invention, there is also provided a method for producing a carboxy group-containing imide urethane resin as described below. [6] A method for producing a carboxyl group-containing imide urethane resin, comprising: a step of polymerizing raw material components including a polyol (a), a polyamine (b), and a tetracarboxylic dianhydride (c) to obtain a carboxyl group-containing polyesterimide resin having a hydroxyl group at its terminal; and a step of reacting the carboxyl group-containing polyesterimide resin with a polyisocyanate (d) to obtain a carboxyl group-containing imide urethane resin.

[0013] Furthermore, according to the present invention, there is provided the following resin composition. [7] A resin composition comprising the carboxy group-containing imide urethane resin according to any one of [1] to [5] above, and an epoxy resin having two or more epoxy groups in one molecule. [8] The resin composition according to [7], further comprising a non-amide organic solvent. [9] The resin composition according to [8], wherein the organic solvent is at least one selected from the group consisting of methyl ethyl ketone, toluene, and dimethyl carbonate. Effect of the Invention

[0014] According to the present invention, it is possible to provide a carboxyl group-containing imide urethane resin that is excellent in flexibility, low water absorption, low dielectric properties, and compatibility with epoxy resins and can be easily dissolved in low-boiling point solvents, as well as a method for producing the same.

[0015] Furthermore, according to the present invention, it is possible to provide a resin composition which is well compatible with an epoxy resin that acts as a curing agent or the like and is capable of forming a cured product such as a cured layer that is excellent in flexibility, low water absorption, heat resistance, and low dielectric properties. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] <Carboxy group-containing imide urethane resin> Hereinafter, the embodiment of the present invention will be described, but the present invention is not limited to the following embodiment. One embodiment of the carboxyl group-containing imido urethane resin of the present invention (hereinafter, also simply referred to as "imido urethane resin") is a resin having a structural unit derived from a carboxyl group-containing polyesterimide resin having a hydroxyl group at its terminal and a structural unit derived from a polyisocyanate (d). The carboxyl group-containing polyesterimide resin has a structural unit derived from a polyol (a), a structural unit derived from a polyamine (b), and a structural unit derived from a tetracarboxylic dianhydride (c). The polyamine (b) is a dimer diamine. Hereinafter, the imido urethane resin of this embodiment will be described in detail.

[0017] (Carboxy group-containing polyesterimide resin) The imide urethane resin of this embodiment is a resin having a structural unit derived from a carboxyl group-containing polyesterimide resin having a hydroxyl group at its terminal (hereinafter, also simply referred to as "carboxyl group-containing polyesterimide resin") and a structural unit derived from a polyisocyanate (d). That is, the imide urethane resin of this embodiment is preferably a reaction product of a carboxyl group-containing polyesterimide resin having a hydroxyl group at its terminal and a polyisocyanate (d). The carboxyl group-containing polyesterimide resin has a structural unit derived from a polyol (a), a structural unit derived from a polyamine (b), and a structural unit derived from a tetracarboxylic dianhydride (c). It is preferable that the carboxyl group-containing polyesterimide resin is substantially composed of only a structural unit derived from a polyol (a), a structural unit derived from a polyamine (b), and a structural unit derived from a tetracarboxylic dianhydride (c).

[0018] [Polyol (a)] The polyol (a) is a compound (diol) having two hydroxyl groups in its molecule. As the polyol (a), it is preferable to use a polycarbonate diol or a polyester diol. In particular, by using a polycarbonate diol as the polyol (a), a cured product such as a cured layer having even better heat resistance can be formed. In addition, by using a polyester diol as the polyol (a), the flexibility of the resin is further improved, and a cured product such as a cured layer having even better flexibility can be formed.

[0019] As the polycarbonate diol, for example, a reaction product of a dialkyl carbonate such as dimethyl carbonate and a diol compound having two hydroxyl groups in the molecule can be used. In addition, a commercially available polycarbonate diol can also be used. As the diol compound, a diol having a straight chain or a side chain having 2 to 10 carbon atoms can be used.

[0020] Examples of the diol compound include aliphatic diols and alicyclic diols. Examples of the aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, and 2-methyl-1,8-octanediol. Examples of the alicyclic diols include 1,4-cyclohexanedimethanol. From the viewpoint of further improving the flexibility of the polyurethane resin, aliphatic diols are preferred, and 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and neopentyl glycol are more preferred.

[0021] Examples of polyester diols include those obtained by condensation polymerization of at least one of aliphatic dicarboxylic acids and aromatic dicarboxylic acids with low molecular weight glycols. Examples of aliphatic dicarboxylic acids include succinic acid, adipic acid, sebacic acid, glutaric acid, and azelaic acid. Examples of aromatic dicarboxylic acids include isophthalic acid and terephthalic acid. Examples of low molecular weight glycols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 3-methylpentanediol, 1,6-hexamethylene glycol, neopentyl glycol, and 1,4-bishydroxymethylcyclohexane.

[0022] As the polyol (a), a polymer polyol other than the above polycarbonate diol or polyester diol can be used. Examples of the polymer polyol other than the polycarbonate diol include polyether polyol, polylactone polyol, dimer diol, and other polymer polyols. Furthermore, a short-chain polyol having a molecular weight of 400 or less can be used in combination. By appropriately using the short-chain polyol, the acid value and urethane bond concentration of the imide urethane resin can be adjusted.

[0023] The number average molecular weight (Mn) of the polyol (a) is preferably 400 to 3,500, more preferably 500 to 2,500. If the number average molecular weight (Mn) of the polyol (a) is less than 400, the urethane bond concentration of the imide urethane resin increases, and the flexibility of the imide urethane resin and the cured product, etc., tends to decrease, and water absorption tends to increase. On the other hand, if the number average molecular weight (Mn) of the polyol (a) is more than 3,500, it may be difficult to increase the acid value of the imide urethane resin, and the heat resistance of the cured product, etc. may decrease.

[0024] [Polyamine (b)] As the polyamine (b), a dimer diamine is used. By using a dimer diamine as the polyamine (b), an imide bond derived from the dimer diamine can be introduced into the imide urethane resin. In general, when an imide bond is introduced into a resin, the heat resistance of the resin increases, but the flexibility and solubility in low boiling point solvents tend to decrease. In contrast, by introducing an imide bond derived from a dimer diamine, not only the heat resistance of the obtained imide urethane resin but also the flexibility and solubility in low boiling point solvents can be increased.

[0025] The carboxyl group-containing polyesterimide resin may further contain a structural unit derived from a polyamine (diamine) other than the polyamine (b) as necessary. Examples of the polyamine (polyamine (b2)) other than the polyamine (b) include aromatic diamines, cyclic aliphatic diamines, and chain aliphatic diamines.

[0026] Aromatic diamines include 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl methane, 3,3'-diaminodiphenyl methane, 3,3'-diaminodiphenyl sulfone, 1,5-diaminonaphthalene, m-phenylenediamine, p-phenylenediamine, 3,3'-dimethyl-4,4'-biphenyldiamine, benzidine, 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl propane, 2,4-diaminotoluene, bis(4-amino-3-carboxyphenyl)methane, 1,3-bis(4-amino bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, bis[4-(4-aminophenoxy)phenyl]sulfone, bis-p-(1,1-dimethyl-5-amino-pentyl)benzene, 1-isopropyl-2,4-m-phenylenediamine, m-xylylenediamine, p-xylylenediamine, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-methylenebis(2,6-xylidine), and α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene.

[0027] Examples of the cyclic aliphatic diamine include di(p-aminocyclohexyl)methane, 1,4-diaminocyclohexane, 1,3-bisaminomethylcyclohexane, isophoronediamine, and norbornanediamine. Examples of the chain aliphatic diamine include hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, diaminopropyltetramethylene, 3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, 2,11-diaminododecane, 1,2-bis-3-aminopropoxyethane, 2,2-dimethylpropylenediamine, 3-methoxyhexamethylenediamine, 2,5-dimethylhexamethylenediamine, 2,5-dimethylheptamethylenediamine, 3-methylheptamethylenediamine, 5-methylnonamethylenediamine, 2,17-diaminoeicosadecane, 1,10-diamino-1,10-dimethyldecane, and 1,12-diaminooctadecane.

[0028] [Tetracarboxylic dianhydride (c)] Examples of the tetracarboxylic dianhydride (b) include esters of trimellitic anhydride and ethylene glycol, 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 3,4'-oxydiphthalic anhydride, 4,4'-oxydiphthalic anhydride, 4,4'-( Examples of the dianhydride include hexafluoroisopropylidene)diphthalic anhydride, ethylene glycol bis(anhydrotrimellitate), p-phenylene bis(trimellitate anhydride), cyclobutane tetracarboxylic dianhydride, methylcyclobutane tetracarboxylic dianhydride, cyclopentane tetracarboxylic dianhydride, 1,2,4,5-cyclohexane tetracarboxylic dianhydride, ethane tetracarboxylic dianhydride, and 3,3',4,4'-bicyclohexyl tetracarboxylic dianhydride.

[0029] From the viewpoint of heat resistance and the like, the tetracarboxylic acid dianhydride (b) is preferably an aromatic tetracarboxylic acid dianhydride, and more preferably an ester of trimellitic anhydride and ethylene glycol, 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic acid dianhydride, or 4,4'-oxydiphthalic anhydride.

[0030] (Polyisocyanate (d)) The imide urethane resin of the present embodiment has a structural unit derived from polyisocyanate (d). The polyisocyanate (c) is preferably a diisocyanate having two isocyanate groups in its molecule. Examples of the diisocyanate include aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates.

[0031] Examples of aromatic diisocyanates include tolylene diisocyanate, 4-methoxy-1,3-phenylene diisocyanate, 4-isopropyl-1,3-phenylene diisocyanate, 4-chloro-1,3-phenylene diisocyanate, 4-butoxy-1,3-phenylene diisocyanate, 2,4-diisocyanate diphenyl ether, diphenylmethane diisocyanate, jurylene diisocyanate, xylylene diisocyanate, 1,5-naphthalene diisocyanate, benzidine diisocyanate, o-nitrobenzidine diisocyanate, and 4,4'-diisocyanate dibenzyl.

[0032] Examples of the aliphatic diisocyanate include methylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate, and 1,10-decamethylene diisocyanate.

[0033] Examples of the alicyclic diisocyanate include 1,4-cyclohexylene diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), 1,5-tetrahydronaphthalene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, and hydrogenated xylylene diisocyanate.

[0034] From the viewpoints of reactivity, heat resistance, flexibility, solubility, and the like, the polyisocyanate (d) is preferably diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), isophorone diisocyanate (IPDI), 1,6-hexamethylene diisocyanate (HDI), 1,5-pentamethylene diisocyanate (PDI), hydrogenated diphenylmethane diisocyanate (HMDI), or the like.

[0035] (Carboxy group-containing imide urethane resin) For example, a conventional polyurethane resin proposed in Patent Document 3 into which an imide bond has been introduced has a structure in which an imide bond and a urethane bond are arranged adjacent to each other, so that hard segments with high intermolecular cohesive force are formed, and flexibility is easily impaired. In addition, the polymerization reaction for forming a polyimide by reacting a polyisocyanate with a tetracarboxylic dianhydride needs to be carried out under high temperature conditions or takes a long time, which is disadvantageous in terms of production.

[0036] In contrast, the imide urethane resin of the present embodiment is a reaction product obtained by reacting the above-mentioned carboxyl group-containing polyesterimide resin having a hydroxyl group at its terminal with the above-mentioned polyisocyanate (d), and therefore has a structure in which the imide bond and the urethane bond are not arranged adjacent to each other, but are arranged at positions spaced apart from each other, unlike the polyurethane resin proposed in Patent Document 3. Therefore, the imide urethane resin of the present embodiment not only has improved heat resistance due to the introduction of the imide bond, but also has excellent flexibility.

[0037] In addition, since the imide urethane resin of the present embodiment has an imide bond derived from dimer diamine, it is superior in flexibility, low water absorption, and low dielectric properties compared to imide urethane resins having imide bonds derived from compounds other than dimer diamine, and can be dissolved well in low boiling point solvents. Furthermore, since the imide urethane resin of the present embodiment has a carboxy group, which is a reaction site with an epoxy group, on the side chain of the polymer chain, it is possible to form a cured product such as a cured layer having a higher crosslink density and better heat resistance when cured using an epoxy resin, compared to urethane resins having a carboxy group at the end of the polymer chain.

[0038] The number average molecular weight (Mn) of the imide urethane resin is preferably 2,000 to 100,000, and more preferably 5,000 to 40,000. If the number average molecular weight of the imide urethane resin is less than 2,000, the film-forming property may be slightly decreased and the heat resistance of the cured product such as the cured layer formed may be decreased. On the other hand, if the number average molecular weight of the imide urethane resin is more than 100,000, the solubility in non-amide organic solvents may be decreased.

[0039] In this specification, the "number average molecular weight (Mn)" of a resin refers to a value calculated as polystyrene measured by gel permeation chromatography (GPC). GPC can be measured, for example, using the following apparatus and conditions.

[0040] (1) Equipment: Product name "HLC-8020" (manufactured by Tosoh Corporation) (2) Column: Product name "TSKgel G2000HXL", "G3000HXL", "G4000GXL" (Tosoh Corporation) (3) Solvent: THF (4)Flow rate: 1.0ml / min (5) Sample concentration: 2g / L (6) Injection volume: 100μL (7) Temperature: 40℃ (8) Detector: Model number "RI-8020" (manufactured by Tosoh Corporation) (9) Standard substance: TSK standard polystyrene (manufactured by Tosoh Corporation)

[0041] The acid value of the imidourethane resin is preferably 5 to 100 mgKOH / g, more preferably 8 to 70 mgKOH / g, and particularly preferably 12 to 35 mgKOH / g. When the acid value of the polyurethane resin is 5 mgKOH / g or more, the crosslinking density of the cured product (crosslinked product) formed by reacting with a curing agent such as an epoxy resin becomes high, and the heat resistance of the cured product can be further improved. Further, when the acid value of the polyurethane resin is 100 mgKOH / g or less, it is possible to suppress an excessive increase in the crosslinking density of the cured product (crosslinked product) formed by reacting with a curing agent such as an epoxy resin. Thereby, generation of strain can be suppressed, and the flexibility of the cured product can be improved.

[0042] The acid value (measured value) of the imidourethane resin can be measured according to the method in accordance with JIS K1557-5:2007 using, as a sample, a solution prepared by dissolving the imidourethane resin in an organic solvent such as methyl ethyl ketone (MEK).

[0043] The imide bond concentration (concentration of imide bonds derived from diamine dimers) of the imidourethane resin is preferably 0.20 to 2.00 mmol / g, more preferably 0.40 to 1.70 mmol / g, and particularly preferably 0.40 to 1.40 mmol / g. When the imide bond concentration is less than 0.20 mmol / g, the low water absorption and low dielectric properties may slightly decrease. On the other hand, when the imide bond concentration exceeds 2.00 mmol / g, the flexibility may slightly decrease.

[0044] "Imide bond concentration" refers to the amount (mmol) of imide bonds per 1 g of imide urethane resin. The imide bond concentration of the imide urethane resin can be controlled, for example, by adjusting the amount (mol) of polyamine (b) and the amount (g) of charged solids including polyol (a) and tetracarboxylic dianhydride (c). The urethane bond concentration (theoretical value) of the imide urethane resin can be calculated by the following formula (A). Imide bond concentration of imide urethane resin (theoretical value) = amount of polyamine (b) (mol) × number of amine groups in polyamine (b) × 1,000 / amount of charged solids (g) (A)

[0045] The urethane bond concentration of the imide urethane resin is preferably 0.20 to 2.00 mmol / g, more preferably 0.40 to 1.70 mmol / g, and particularly preferably 0.55 to 1.40 mmol / g. If the urethane bond concentration is less than 0.20 mmol / g, the compatibility with the epoxy resin may be slightly decreased. If the urethane bond concentration of the imide urethane resin is more than 2.00 mmol / g, the compatibility with the epoxy resin may be further increased, but the flexibility and low water absorption may be slightly decreased.

[0046] "Urethane bond concentration" refers to the amount (mmol) of urethane bonds per 1 g of imide urethane resin. The urethane bond concentration of the imide urethane resin can be controlled, for example, by adjusting the amount (mol) of polyisocyanate (d) and the amount (g) of charged solids including polyol (a) and tetracarboxylic dianhydride (c). The urethane bond concentration (theoretical value) of the imide urethane resin can be calculated from the following formula (B). Urethane bond concentration of imide urethane resin (theoretical value) = amount of polyisocyanate (d) (mol) × number of isocyanate groups in polyisocyanate (d) × 1,000 / amount of charged solids (g) (B)

[0047] The higher the urethane bond concentration of the imide urethane resin, the more the compatibility with the epoxy resin tends to improve. However, when the urethane bond concentration is within a certain range, the compatibility with the epoxy resin tends to decrease as the imide bond concentration increases. That is, from the viewpoint of further improving the compatibility with the epoxy resin, the balance between the urethane bond concentration and the imide bond concentration is important. Specifically, the ratio (urethane / imide) of the urethane bond concentration (mmol / g) to the imide bond concentration (mmol / g) of the imide urethane resin is preferably 0.1 to 5.0, more preferably 0.3 to 3.2. If the value of the above ratio is less than 0.1, the effect of improving the compatibility with the epoxy resin may be slightly decreased. On the other hand, if the value of the above ratio is more than 5.0, the low water absorption and low dielectric properties may be slightly decreased.

[0048] The total concentration of urethane bonds and imide bonds in the imide urethane resin is preferably 0.5 to 4.0 mmol / g, more preferably 0.8 to 3.2 mmol / g. If the total concentration of urethane bonds and imide bonds is less than 0.8 mmol / g, the effect of improving heat resistance and low dielectric properties may be slightly reduced. On the other hand, if the total concentration of urethane bonds and imide bonds exceeds 3.2 mmol / g, flexibility may be slightly reduced.

[0049] (Method of manufacturing imide urethane resin) The imide urethane resin can be produced, for example, according to the method shown below. First, polyol (a), polyamine (b), tetracarboxylic dianhydride (c), and organic solvent are mixed and reacted at 100 to 150°C for about 1 to 7 hours while stirring to obtain a carboxyl group-containing polyesterimide resin having a hydroxyl group at its terminal. Next, polyisocyanate (d) is added so that the molar ratio of hydroxyl groups to isocyanate groups is approximately 1.0 (OH / NCO ≒ 1.0), and the reaction is carried out at 50 to 120°C for about 1 to 12 hours. Thereafter, the mixture is diluted with an organic solvent as necessary and cooled to obtain the desired carboxyl group-containing imide urethane resin in the form of a resin solution.

[0050] As the organic solvent, it is preferable to use an organic solvent that does not react with any of the polyol (a), the polyamine (b), the tetracarboxylic dianhydride (c), and the polyisocyanate (d). In particular, it is preferable to use a non-amide organic solvent. By reacting using a non-amide organic solvent, the obtained imide urethane resin solution can be used as it is as a paint or composition, and can be dried or cured at a low temperature in a short time.

[0051] Examples of non-amide organic solvents include toluene, cyclohexane, methylcyclohexane, ethylene glycol diethyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, methyl methoxypropionate, ethyl methoxypropionate, ethyl acetate, n-butyl acetate, isoamyl acetate, acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, dimethyl carbonate, tetrahydrofuran, and dioxane. Among these, from the viewpoints of the solubility of the imide urethane resin and ease of drying, etc., toluene, methyl ethyl ketone, dimethyl carbonate, cyclopentanone, and cyclohexanone are preferred, and toluene, methyl ethyl ketone, and dimethyl carbonate are more preferred.

[0052] <Resin composition> One embodiment of the resin composition of the present invention contains the above-mentioned carboxyl group-containing imide urethane resin and an epoxy resin having two or more epoxy groups in one molecule. That is, by reacting the above-mentioned imide urethane resin with an epoxy resin as a curing agent to cure it, a cured product such as a cured layer having excellent flexibility, low water absorption, heat resistance, and low dielectric properties can be formed.

[0053] The epoxy resin used as the curing agent has two or more epoxy groups in one molecule. Examples of such epoxy resins include bisphenol A type epoxy resins, hydrogenated bisphenol A type epoxy resins, bisphenol F type epoxy resins, brominated bisphenol A type epoxy resins, phenol novolac type epoxy resins, o-cresol novolac type epoxy resins, flexible epoxy resins, epoxidized polybutadiene, amine type epoxy resins, heterocycle-containing epoxy resins, alicyclic epoxy resins, bisphenol S type epoxy resins, dicyclopentadiene type epoxy resins, triglycidyl isocyanurate, bixylenol type epoxy resins, and compounds having a glycidyl group.

[0054] The epoxy equivalent of the epoxy resin is preferably 100 to 10,000 g / eq, and more preferably 100 to 600 g / eq, from the viewpoints of the mechanical strength, flexibility, heat resistance, and the like of the cured product to be formed.

[0055] The number average molecular weight (Mn) of the epoxy resin is preferably from 100 to 100,000, and more preferably from 300 to 70,000, from the viewpoint of compatibility with the imide urethane resin to be reacted.

[0056] By adjusting the molar ratio of the epoxy group in the epoxy resin and the carboxyl group in the imide urethane resin, a cured product having desired properties can be obtained. For example, it is preferable to react the epoxy resin and the imide urethane resin in an amount such that the epoxy group / carboxyl group (molar ratio) is 10 / 1 to 1 / 1. If the molar ratio is outside the above range, the crosslinking property is likely to decrease, and the heat resistance of the obtained cured product may be slightly decreased.

[0057] In the resin composition, the content of the epoxy resin is preferably 5 to 200 parts by mass, more preferably 10 to 100 parts by mass, per 100 parts by mass of the imide urethane resin (solid content). By making the content of the epoxy resin 5 parts by mass or more per 100 parts by mass of the imide urethane resin, the crosslinking property becomes better. In addition, by making the content of the epoxy resin 200 parts by mass or less per 100 parts by mass of the imide urethane resin, the crosslinking property is less likely to decrease, and the heat resistance of the obtained cured product can be further improved.

[0058] The resin composition can be prepared by mixing the epoxy resin and the imide urethane resin described above in a desired ratio. During preparation, they may be mixed in the presence of the organic solvent described above, or the epoxy resin may be added to a solution of the imide urethane resin and mixed. That is, the resin composition of the present embodiment may further contain an organic solvent. By using an organic solvent with a low boiling point, it can be used as a coating composition. When used as a coating composition, it can be dried and cured at low temperatures and can be used as an adhesive having excellent properties such as heat resistance and adhesion. Such a coating composition is useful, for example, as an adhesive for electronic components and a coating composition for forming an insulating protective film. In addition, the coating composition can be used for applications such as solder resist, electromagnetic shielding film, and coating material, and as an adhesive for flexible printed circuit boards, conductive adhesives, and adhesives for structural materials.

[0059] The organic solvent is preferably an organic solvent capable of dissolving both the epoxy resin and the imide urethane resin. In consideration of use as a coating composition, it is preferable to use a non-amide organic solvent that has relatively little effect on the environment and the human body. It is also preferable to use a non-nitrogen organic solvent whose boiling point is 170°C or less. By using an organic solvent whose boiling point is 170°C or less, drying and curing can be performed under lower temperature conditions.

[0060] As the organic solvent, the same organic solvent as that described above that can be used when producing the imide urethane resin can be used.Specifically, toluene, cyclohexane, methylcyclohexane, ethylene glycol diethyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, methyl methoxypropionate, ethyl methoxypropionate, ethyl acetate, n-butyl acetate, isoamyl acetate, acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, dimethyl carbonate, etc. can be used.Of these, toluene, methyl ethyl ketone, and dimethyl carbonate are preferred from the viewpoints of the solubility of epoxy resins and imide urethane resins, and drying efficiency when used as a coating composition.

[0061] The resin composition may further contain other components other than the imide urethane resin, epoxy resin, and organic solvent as necessary, such as a curing accelerator, an isocyanate-based crosslinking agent, a thermoplastic polymer, a tackifier resin, a pigment, an antioxidant, an ultraviolet absorber, a surfactant, and a filler.

[0062] The resin composition of the present embodiment can be cured, for example, by applying it to a desired substrate or the like and then maintaining it under a temperature condition of preferably 40 to 200°C, more preferably 130 to 180°C. EXAMPLES

[0063] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the examples and comparative examples, "parts" and "%" are by mass unless otherwise specified.

[0064] <Preparing materials> The following various materials were prepared:

[0065] (Polyol) UH-100: Product name "Ethanacole UH-100", manufactured by UBE, polyhexamethylene carbonate diol, number average molecular weight 984 UH-200: Product name "Ethanacole UH-200", manufactured by UBE, polyhexamethylene carbonate diol, number average molecular weight 1,968 P-1050: Trade name "Kuraray Polyol P-1050", manufactured by Kuraray Co., Ltd., polyester polyol of 3-methyl-1,5-pentanediol and sebacic acid, number average molecular weight 988 1,6-HD: 1,6-Hexanediol PP2033: Product name "Pripol 2033", manufactured by CRODA, dimer diol, number average molecular weight 505

[0066] (Polyamine) P1074: Trade name "Priamine 1074", manufactured by CRODA, dimer diamine, number average molecular weight 529 ODA: 4,4'-diaminodiphenyl ether 1,3-BAC: 1,3-bisaminomethylcyclohexane

[0067] (acid anhydride) TMEG-100: Product name "Rikacid TMEG-100", manufactured by New Japan Chemical Co., Ltd., ester of trimellitic anhydride and ethylene glycol BPADA: 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride

[0068] (Polyisocyanate) ·TDI: Tolylene diisocyanate IPDI: Isophorone diisocyanate

[0069] (hardening agent) Epoxy resin A: Product name "YD-017", Nippon Steel Chemical & Material Co., Ltd., bisphenol A type epoxy resin, epoxy equivalent 1,900g / eq Epoxy resin B: Product name "XD-1000", Nippon Kayaku Co., Ltd., phenol novolac type epoxy resin, epoxy equivalent 252g / eq.

[0070] <Resin manufacturing> Example 1 In a separable flask equipped with a stirrer, 100.0 parts (0.10 mol) of UH-100, 61.0 parts (0.12 mol) of P1074, 64.0 parts (0.16 mol) of TMEG-100, and 40.7 parts of toluene were placed. The mixture was reacted at 130°C for 4 hours to obtain a carboxyl group-containing polyesterimide resin having a hydroxyl group at its end. After diluting with 132.4 parts of toluene, 9.9 parts (0.06 mol) of TDI was added and the mixture was reacted at 90°C for 4 hours. Infrared absorption spectrum analysis revealed that the 2,270 cm -1 After confirming that the absorption of methyl ethyl ketone had disappeared, 173.1 parts was added to dilute the solution and cooled to room temperature to obtain a solution of resin A with a solid concentration of 40%. The number average molecular weight (Mn) of the obtained resin A was 30,000, the imide bond concentration derived from the dimer diamine calculated from the amount of the materials charged was 1.00 mmol / g, the urethane bond concentration was 0.50 mmol / g, and the acid value (actual measured value) was 20 mgKOH / g.

[0071] Comparative Example 1 In a separable flask equipped with a stirrer, 100.0 parts (0.10 mol) of UH-100 and 9.2 parts (0.02 mol) of TMEG-100 were placed. The mixture was allowed to react at 100°C for 2 hours to obtain a carboxyl group-containing polyester resin having a hydroxyl group at its end. After diluting with 21.5 parts of toluene, 12.9 parts (0.08 mol) of TDI was added and the mixture was allowed to react at 90°C for 4 hours. Infrared absorption spectrum analysis revealed that the 2,270 cm -1After confirming that the absorption of methyl ethyl ketone had disappeared, 91.6 parts of methyl ethyl ketone was added to dilute the solution, which was then cooled to room temperature to obtain a solution of resin M with a solid content of 40%. The number average molecular weight (Mn) of resin M was 30,000, the urethane bond concentration calculated from the amount of the materials charged was 1.2 mmol / g, and the acid value (measured value) was 20 mg KOH / g.

[0072] Comparative Example 2 In a separable flask equipped with a stirrer, 100.0 parts (0.10 mol) of UH-100, 3.0 parts (0.03 mol) of 1,6-HD, 18 parts (0.09 mol) of ODA, 50.7 parts (0.12 mol) of TMEG-100, and 183.7 parts of N-methyl-2-pyrrolidone (NMP) were placed. The mixture was reacted at 150°C for 4 hours to obtain a carboxyl group-containing polyesterimide resin having a hydroxyl group at its terminal. 15.2 parts (0.09 mol) of TDI was added and the mixture was reacted at 90°C for 4 hours. Infrared absorption spectrum analysis revealed that the 2,270 cm -1 After confirming that the absorption of 1.0 ppm had disappeared, 91.9 parts of NMP was added to dilute the solution, which was then cooled to room temperature to obtain a solution of Resin N with a solid content of 40%. The number average molecular weight (Mn) of Resin N was 30,000, the imide bond concentration calculated from the amount of the materials charged was 1.0 mmol / g, the urethane bond concentration was 1.0 mmol / g, and the acid value (measured value) was 20 mg KOH / g.

[0073] Comparative Example 5 According to the description of Patent Document 3, an imide urethane resin having an imide bond formed by the reaction of a polyisocyanate with a tetracarboxylic dianhydride was produced. 100.0 parts (0.10 mol) of UH-100 and 169.7 parts of NMP were placed in a separable flask equipped with a stirrer. After heating to 60°C, 40.6 parts (0.18 mol) of IPDI was added and reacted at 100°C for 2 hours. 32.7 parts (0.11 mol) of BPDA was added and reacted at 150°C for 3 hours. Infrared absorption spectrum analysis revealed that the 2,270 cm -1It was confirmed that the absorption at the end of the reaction had disappeared, and an imide urethane resin having an acid anhydride group at its terminal was obtained. 3.5 parts (0.03 mol) of 1,6-HD was added and the reaction was carried out at 120°C for 3 hours. Infrared absorption spectrum analysis revealed that the 1,850 cm -1 After confirming that the absorption of 100% had disappeared, 84.9 parts of NMP was added to dilute the solution, which was then cooled to room temperature to obtain a solution of resin Q with a solid content of 40%. The number average molecular weight (Mn) of resin Q was 10,000, the imide bond concentration calculated from the amounts of the materials charged was 1.0 mmol / g, the urethane bond concentration was 1.2 mmol / g, and the acid value (measured value) was 20 mg KOH / g.

[0074] (Examples 2 to 12) Solutions of resins B to L with a solid content concentration of 40% were obtained in the same manner as in Example 1 above, except that the compositions shown in Table 1-1 were used. The physical properties of the obtained resins are shown in Table 1-1.

[0075] (Comparative Examples 3 to 4, 6 to 7) Except for using the formulations shown in Table 1-2, solutions of Resins O to P and R to S were obtained in the same manner as in the above-mentioned Comparative Examples 1 and 2. The physical properties of the obtained resins are shown in Table 1-2.

[0076] <Resin evaluation> (Solubility in low boiling point solvents) The resin solution was applied to a PET film so that the thickness after drying was 40 μm, and then dried under heating conditions to prepare a test piece. The obtained test piece was cut to a size of 500 mm x 500 mm, and then immersed in methyl ethyl ketone (MEK) at room temperature for 10 minutes. The test piece was then dried in an oven at 120°C for 3 minutes, and the state of the coating film on the PET film was observed, and the solubility of the resin in a low boiling point solvent was evaluated according to the following evaluation criteria. The results are shown in Tables 1-1 and 1-2. ◯: No undissolved coating film remained on the PET film. ×: Undissolved coating film remained on the PET film.

[0077] (Flexibility) The resin solution was applied to a release paper so that the thickness after drying was 40 μm, and then dried under heating conditions to form a coating film (dried film). The formed coating film was cut to a size of 60 mm in length x 15 mm in width to obtain a test piece. The obtained test piece was subjected to a tensile test in accordance with JIS K-7127:1999 at room temperature (25°C) using an autograph (product name "AGS-J", manufactured by Shimadzu Corporation). The 20% modulus value of the test piece was then measured, and the flexibility of the resin was evaluated according to the following evaluation criteria. The results are shown in Tables 1-1 and 1-2. ⊚: The 20% modulus value was less than 5 MPa. ◯: The 20% modulus value was 5 MPa or more and less than 10 MPa. △: The 20% modulus value was 10 MPa or more and less than 20 MPa. ×: The 20% modulus value was 20 MPa or more.

[0078] (Low water absorption) The resin solution was applied to a release paper so that the thickness after drying was 40 μm, and then dried under heating conditions to form a coating film (dried film). After folding so that the thickness of the coating film was about 300 μm, it was heat-pressed using a thermal laminator under conditions of 150 ° C and 0.1 MPa. Then, it was cut to a size of 500 × 500 mm to obtain a test piece. The obtained test piece was immersed in pure water at 25 ° C for 24 hours. The mass of the test piece before and after immersion was measured, and the water absorption rate was calculated from the following formula (C), and the low water absorption of the resin was evaluated according to the evaluation criteria shown below. The results are shown in Tables 1-1 and 1-2. Water absorption rate (%) = (mass of test piece before immersion / mass of test piece after immersion) x 100 (C) A: The water absorption rate was less than 1.0%. △: The water absorption rate was 1.0% or more and less than 1.5%. ×: The water absorption rate was 1.5% or more.

[0079] (Dielectric constant / dielectric tangent) The resin solution was applied to a release paper so that the thickness after drying was 40 μm, and then dried under heating conditions to form a coating film (dried film). After folding so that the coating film had a thickness of about 150 μm, a thermal laminator was used to thermocompress the film under conditions of 150°C and 0.1 MPa to prepare a test piece. The relative dielectric constant and dielectric loss tangent of this test piece were measured at a measurement temperature of 23°C and a measurement frequency of 1 GHz using a dielectric constant measuring device (manufactured by AET·Anritsu) by the cavity resonator method. The low dielectric properties of the resin were then evaluated according to the following evaluation criteria. The results are shown in Tables 1-1 and 1-2. [Evaluation criteria for dielectric constant] A: The relative dielectric constant was less than 2.8. △: The relative dielectric constant was 2.8 or more and less than 3.0. ×: The relative dielectric constant was 3.0 or more. [Evaluation criteria for dielectric tangent] A: The dielectric tangent was less than 0.010. △: The dielectric tangent was 0.010 or more and less than 0.013. ×: The dielectric tangent was 0.013 or more.

[0080] TIFF2025079886000001.tif222170

[0081] TIFF2025079886000002.tif236170

[0082] <Production of Resin Composition> (Examples 13 to 24, Comparative Examples 8 to 14) The solution of the base agent (resin) and the curing agent (epoxy resin) were mixed to obtain the composition shown in Table 2, thereby obtaining a resin composition.

[0083] <Evaluation of Resin Composition> (Compatibility with epoxy resin) The appearance of the resin composition was observed, and the compatibility with the epoxy resin was evaluated according to the following criteria. The results are shown in Table 2. ○: The appearance was completely transparent. △: Appearance was slightly opaque. ×: The appearance was completely opaque.

[0084] (Heat resistance) The resin composition was applied to a release paper so that the thickness after drying was 40 μm, and then dried under heating conditions to form a coating film (dried film). The formed coating film was heated at 150° C. for 3 hours and thermally cured to obtain a test piece (cured film). The linear expansion coefficient (CTE, 25 to 275° C.) of the obtained test piece was measured under the conditions shown below, and the heat resistance of the cured film was evaluated according to the criteria shown below. The results are shown in Table 2. (1) Equipment: Product name: Thermomechanical analyzer TMA-7100E (manufactured by Hitachi High-Tech Science Corporation) (2) Probe: Quartz tensile probe (3) Load: 10mN (4) Heating rate: 5℃ / min (5) Measurement temperature range: 20 to 320°C (6) Sample length: 10 mm ◯: CTE was less than 300 ppm / ° C. △: CTE was 300 ppm / ℃ or more and less than 500 ppm / ℃. ×: CTE was 500 ppm / ° C. or more.

[0085] (Flexibility) The resin composition was applied to a release paper so that the thickness after drying was 40 μm, and then dried under heating conditions to form a coating film (dried film). The formed coating film was heated at 150° C. for 3 hours and thermally cured to form a cured film. The formed cured film was cut to a size of 60 mm long x 15 mm wide to obtain a test piece. The obtained test piece was subjected to a tensile test in accordance with JIS K-7127:1999 using an autograph (product name "AGS-J", manufactured by Shimadzu Corporation) at room temperature (25° C.). The 100% modulus value of the test piece was then measured, and the flexibility of the cured film was evaluated according to the following evaluation criteria. The results are shown in Table 2. ⊚: The 20% modulus value was less than 5 MPa. ◯: The 20% modulus value was 5 MPa or more and less than 15 MPa. △: The 20% modulus value was 15 MPa or more and less than 30 MPa. ×: The 20% modulus value was 30 MPa or more.

[0086] (Low water absorption) The resin composition was applied to a release paper so that the thickness after drying was 40 μm, and then dried under heating conditions to form a coating film (dried film). After folding so that the thickness of the coating film was about 300 μm, it was thermocompressed using a heat press under conditions of 100 ° C and 1 MPa. Next, it was heated at 150 ° C for 3 hours, thermally cured to form a cured film, and then cut to a size of 500 × 500 mm to obtain a test piece. The obtained test piece was immersed in pure water at 25 ° C for 24 hours. The mass of the test piece before and after immersion was measured, and the water absorption rate was calculated from the following formula (C), and the low water absorption of the cured film was evaluated according to the evaluation criteria shown below. The results are shown in Table 2. Water absorption rate (%) = (mass of test piece before immersion / mass of test piece after immersion) x 100 (C) ○: The water absorption rate was less than 0.5%. △: The water absorption rate was 0.5% or more and less than 1.0%. ×: The water absorption rate was 1.0% or more.

[0087] (Dielectric constant / dielectric tangent) The resin composition was applied to a release paper so that the thickness after drying was 40 μm, and then dried under heating conditions to form a coating film (dried film). After folding so that the thickness of the coating film was about 150 μm, it was thermocompressed using a thermal laminator under conditions of 150 ° C and 0.1 MPa. Furthermore, it was heated at 150 ° C for 3 hours and thermally cured to form a test piece. The relative dielectric constant and dielectric loss tangent of this test piece were measured at a measurement temperature of 23 ° C and a measurement frequency of 1 GHz using a dielectric constant measuring device (manufactured by AET Anritsu Co., Ltd.) by the cavity resonator method. The low dielectric properties of the cured film were then evaluated according to the following evaluation criteria. The results are shown in Table 2. [Evaluation criteria for dielectric constant] A: The relative dielectric constant was less than 2.8. △: The relative dielectric constant was 2.8 or more and less than 3.0. ×: The relative dielectric constant was 3.0 or more. [Evaluation criteria for dielectric tangent] ◯: The dielectric tangent was less than 0.010. △: The dielectric tangent was 0.010 or more and less than 0.013. ×: The dielectric tangent was 0.013 or more.

[0088] TIFF2025079886000003.tif184170 [Industrial Applicability]

[0089] The carboxyl group-containing imide urethane resin of the present invention is useful, for example, as a material for flexible substrates.

Claims

1. The polyesterimide resin has a structural unit derived from a carboxyl group-containing polyesterimide resin having a hydroxyl group at its terminal, and a structural unit derived from a polyisocyanate (d), the carboxy group-containing polyesterimide resin has a structural unit derived from a polyol (a), a structural unit derived from a polyamine (b), and a structural unit derived from a tetracarboxylic dianhydride (c); The carboxy group-containing imide urethane resin, wherein the polyamine (b) is a dimer diamine.

2. 2. The carboxyl group-containing imide urethane resin according to claim 1, having a number average molecular weight of 2,000 to 100,000.

3. 2. The carboxyl group-containing imide urethane resin according to claim 1, having an acid value of 5 to 100 mgKOH / g.

4. 2. The carboxyl group-containing imide urethane resin according to claim 1, wherein the imide bond concentration is 0.20 to 2.00 mmol / g.

5. 2. The carboxyl group-containing imide urethane resin according to claim 1, wherein the urethane bond concentration is 0.20 to 2.00 mmol / g.

6. a step of polymerizing raw material components including a polyol (a), a polyamine (b), and a tetracarboxylic dianhydride (c) to obtain a carboxyl group-containing polyesterimide resin having a hydroxyl group at its terminal; and a step of reacting the carboxyl group-containing polyesterimide resin with a polyisocyanate (d) to obtain a carboxyl group-containing imide urethane resin.

7. The carboxyl group-containing imide urethane resin according to any one of claims 1 to 5, and an epoxy resin having two or more epoxy groups in one molecule.

8. The resin composition according to claim 7, further comprising a non-amide organic solvent.

9. The resin composition according to claim 8, wherein the organic solvent is at least one selected from the group consisting of methyl ethyl ketone, toluene, and dimethyl carbonate.

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