Moisture-curable polyurethane hot melt resin composition, coating agent, adhesive, hardened product, and article and method for manufacturing article

Abstract

The present invention aims to provide a moisture-curing polyurethane hot melt resin composition, coating agent, adhesive, cured product, and article, as well as a method for manufacturing the article, which have high spray adaptability, can form a thin film with high moisture resistance, and are capable of forming a film. A moisture-curing polyurethane hot melt resin composition contains a urethane prepolymer (i) having isocyanate groups. In the moisture-curing polyurethane hot melt resin composition, the urethane prepolymer (i) is a reaction product of a polyol (A) and a polyisocyanate (B). The polyol (A) must at least include an alicyclic polyester polyol (a1), a crystalline polyester polyol (a2), and an aromatic polyester polyol (a3). The content of the alicyclic polyester polyol (a1) in the polyol (A) is 50% by mass or more.

Description

Technical Field

[0001] This disclosure relates to a moisture-curing polyurethane hot melt resin composition, a coating agent, an adhesive, a cured material, and an article and a method of manufacturing the article. Background Technology

[0002] In the manufacture of electronic devices, to protect printed circuit boards or components from moisture and other harmful substances, a "conformal coating" technique is known, which involves applying an extremely thin layer of moisture-resistant coating agent to the surface of the board or electronic component. Solvent-based urethane resins have conventionally been used as moisture-resistant coating agents (see, for example, Patent Document 1).

[0003] [Existing technical documents]

[0004] [Patent Literature]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 5-275487 Summary of the Invention

[0006] [The problem the invention aims to solve]

[0007] However, solvent-based moisture-proof coatings present safety and environmental concerns related to the solvent. Furthermore, to achieve sufficient moisture resistance, there is a tendency towards thicker coatings, requiring thinner coatings with high moisture resistance.

[0008] On the other hand, when using non-solvent-based moisture-proof coating agents instead of solvent-based ones, if a coating film is to be formed by spray coating, stringing and other issues may easily occur, making spray coating sometimes unsuitable.

[0009] Therefore, the inventors have made efforts to solve the problems of solvent-based moisture-proof coating agents and existing non-solvent-based moisture-proof coating agents. As a result, as a non-solvent-based moisture-proof coating agent, a moisture-curing polyurethane hot melt resin composition with high spray adaptability and moisture-proof properties that can form a thin film (cured film) with high moisture-proof performance is known.

[0010] That is, the purpose of this disclosure is to provide a moisture-curing polyurethane hot melt resin composition that has high spray adaptability, can form a thin film and has high moisture resistance.

[0011] In addition, the present disclosure aims to provide a coating agent and a cured product using the moisture-curing polyurethane hot melt resin composition, as well as an article and a method for manufacturing the article.

[0012] [Technical means to solve the problem]

[0013] This disclosure has the following implementation methods.

[0014] [1] A moisture-curing polyurethane hot melt resin composition comprising a urethane prepolymer (i) having an isocyanate group, wherein the urethane prepolymer (i) is a reaction product of a polyol (A) and a polyisocyanate (B), wherein the polyol (A) must contain at least an alicyclic polyester polyol (a1), a crystalline polyester polyol (a2), and an aromatic polyester polyol (a3), wherein the content of the alicyclic polyester polyol (a1) in the polyol (A) is 50% by mass or more.

[0015] [2] A moisture-curing polyurethane hot melt resin composition comprising a urethane prepolymer (i) having an isocyanate group, wherein the urethane prepolymer (i) is a reaction product of a polyol (A) and a polyisocyanate (B), wherein the polyol (A) must contain at least an alicyclic polyester polyol (a1), a crystalline polyester polyol (a2), and an aromatic polyester polyol (a3), wherein the content of the crystalline polyester polyol (a2) is 10% to 30% by mass, the content of the aromatic polyester polyol (a3) ​​is 10% to 30% by mass, and the content of the high molecular weight polycaprolactone polyol (a4) in the polyol (A) is less than 10% by mass.

[0016] [3] A moisture-curing polyurethane hot melt resin composition comprising a urethane prepolymer (i) having an isocyanate group, wherein the urethane prepolymer (i) in the moisture-curing polyurethane hot melt resin composition is a reaction product of a polyol (A) and a polyisocyanate (B), wherein the polyol (A) must at least comprise an alicyclic polyester polyol (a1), a crystalline polyester polyol (a2), and an aromatic polyester polyol (a3), wherein the content of the crystalline polyester polyol (a2) is 10% to 30% by mass, the content of the aromatic polyester polyol (a3) ​​is 10% to 30% by mass, and the melt viscosity of the moisture-curing polyurethane hot melt resin composition at 120°C is 5 Pa. Below s.

[0017] [4] The moisture-curing polyurethane hot melt resin composition according to any one of [1] to [3], wherein the alicyclic polyester polyol (a1) comprises at least an alicyclic polyester polyol (a1-1) having structural units derived from branched aliphatic polyols and structural units derived from alicyclic polyacids.

[0018] [5] The moisture-curing polyurethane hot melt resin composition according to any one of [1] to [4], wherein the content of high molecular weight polycaprolactone polyol (a4) in the polyol (A) is less than 10% by mass.

[0019] [6] The moisture-curing polyurethane hot melt resin composition according to any one of [1] to [5], wherein the melt viscosity at 120°C is 5 Pa. Below s.

[0020] [7] A coating agent comprising a moisture-curing polyurethane hot melt resin composition according to any one of [1] to [6].

[0021] [8] An adhesive comprising a moisture-curing polyurethane hot melt resin composition according to any one of [1] to [6].

[0022] [9] A cured product is a cured product of the moisture-curing polyurethane hot melt resin composition according to any one of [1] to [6].

[0023]

[10] An article having a cured form of a moisture-curing polyurethane hot melt resin composition according to any one of [1] to [6].

[0024]

[11] An article having a cured form of the moisture-curing polyurethane hot melt resin composition described in any one of [1] to [6] on an electronic circuit board.

[0025]

[12] A method of manufacturing an article, wherein a moisture-curing polyurethane hot melt resin composition according to any one of [1] to [6] is spray-coated onto an object.

[0026]

[13] A method of manufacturing an article, wherein an electronic circuit board or an electronic component on the electronic circuit board is spray-coated with a moisture-curing polyurethane hot melt resin composition according to any one of [1] to [6].

[0027] [The effects of the invention]

[0028] The moisture-curing polyurethane hot melt resin composition disclosed herein exhibits high spray adaptability and can form a thin, highly moisture-resistant cured film through spray coating. In particular, the moisture-curing polyurethane hot melt resin composition disclosed herein is preferably used as a conformal coating agent. Detailed Implementation

[0029] I. Moisture-curing polyurethane hot melt resin composition

[0030] The moisture-curing polyurethane hot melt resin composition disclosed herein (sometimes referred to in this specification as "the resin composition of this disclosure" or "this resin composition") contains a urethane prepolymer (i) having an isocyanate group. The urethane prepolymer (i) is the reaction product of a polyol (A) and a polyisocyanate (B), wherein the polyol (A) must comprise at least an alicyclic polyester polyol (a1), a crystalline polyester polyol (a2), and an aromatic polyester polyol (a3).

[0031] The moisture-curing polyurethane hot melt resin composition disclosed herein has high spray adaptability and can be easily formed into a thin and highly moisture-proof cured film by spray coating.

[0032] [Carbamate prepolymer (i)]

[0033] The urethane prepolymer (i) in this disclosure is a reaction product of a polyol (A) and a polyisocyanate (B). In other words, the urethane prepolymer (i) comprises structural units derived from the polyol (A) and structural units derived from the polyisocyanate (B).

[0034] <Polyol (A)>

[0035] The polyol (A) must include at least alicyclic polyester polyol (a1), crystalline polyester polyol (a2), and aromatic polyester polyol (a3).

[0036] <<Alicyclic Polyester Polyols (a1)>>

[0037] The alicyclic polyester polyol (a1) is a polyester polyol with structural units derived from alicyclic polyacids.

[0038] Examples of polyester polyols with structural units derived from alicyclic polyacids include: alicyclic polyester polyols with structural units derived from branched aliphatic diols and alicyclic polyacids (a1-1), and alicyclic polyester polyols with structural units derived from linear aliphatic diols and alicyclic polyacids (a1-2).

[0039] -Alicyclic polyester polyol (a1-1)-

[0040] The alicyclic polyester polyol (a1-1) has structural units derived from branched aliphatic diols and structural units derived from alicyclic polyacids. In other words, the alicyclic polyester polyol (a1-1) is a reaction product of a polyol with a branched aliphatic diol as the main component and a polyacid with an alicyclic polyacid as the main component, as essential raw materials. The alicyclic polyester polyol (a1-1) has hydroxyl groups, preferably two or more.

[0041] Branched aliphatic diols are compounds containing a main chain having two or more hydroxyl groups in its straight-chain portion and at least one side chain group bonded to the main chain. The side chain group of a branched aliphatic diol is preferably alkyl, specifically including methyl, ethyl, propyl, butyl, pentyl, hexyl, etc.

[0042] Examples of branched aliphatic diols include: 1,2-propanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol (3MPD), 2-ethyl-2-butylpropanediol, 2-methylpropanediol, neopentyl glycol (2,2-dimethyl-1,3-propanediol), 2-methyl-2-butyl-1,3-propanediol, 2,2-propanediol, etc. Branched aliphatic diols such as 4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, and 2,4-diethyl-1,5-pentanediol; and lactone-based ring-opening polymerized polyester polyols obtained by ring-opening polymerization of cyclic ester compounds (i.e., lactones) containing side chains, such as pentane-4-lactone compounds, γ-pentanediol compounds, and 4,4-dimethyltetrahydro-2H-pyran-2-one compounds. These can be used alone or in combination of two or more. From the viewpoint of balancing a suitable open time at low temperatures with moisture-proof performance, one or more of the following groups are preferred: neopentanediol, 3-methyl-1,5-pentanediol, and 2-methyl-1,3-propanediol.

[0043] The polyol used as a raw material for the alicyclic polyester polyol (a1-1) must contain branched aliphatic diols; however, the inclusion of polyols other than branched aliphatic diols is permitted as long as it does not impair the functionality derived from the alicyclic polyester polyol (a1-1). The content of branched aliphatic diols in the polyol used as a raw material for the alicyclic polyester polyol (a1-1) is preferably 85% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably substantially 100% by mass.

[0044] Examples of alicyclic polycarboxylic acids include: 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,2-cyclopropanedicarboxylic acid, 1,2-cyclobutanedicarboxylic acid, 1,3-cyclobutanedicarboxylic acid, 1,2-cyclopentanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cycloheptanedicarboxylic acid, 1,3-cycloheptanedicarboxylic acid, 1,4-cycloheptanedicarboxylic acid, 1,2-cyclooctanedicarboxylic acid, 1,3-cyclooctanedicarboxylic acid, 1,4-cyclooctanedicarboxylic acid, 1,5-cyclooctanedicarboxylic acid, 1,2-cyclononanedicarboxylic acid, 1,3-cyclononanedicarboxylic acid, and 1,4-cyclononanedicarboxylic acid. Acids, 1,5-cyclononanedicarboxylic acid, 1,2-cyclodecanedicarboxylic acid, 1,3-cyclodecanedicarboxylic acid, 1,4-cyclodecanedicarboxylic acid, 1,5-cyclodecanedicarboxylic acid, 1,6-cyclodecanedicarboxylic acid, 1,2,3-cyclopropanetricarboxylic acid, 1,2,3-cyclobutanetricarboxylic acid, 1,2,3-cyclopentanetricarboxylic acid, 1,2,3-cycloheptanetricarboxylic acid, 1,2,3-cyclohexanetricarboxylic acid, dicyclohexyl-4,4'-dicarboxylic acid and dimer acids, 1,2-cyclohexanediacetic acid, 1,3-cyclohexanediacetic acid, 1,4-cyclohexanediacetic acid and their anhydrides; anhydrides of hydrogenated phthalic acid, etc., cyclohexanedipic acid esters, etc. These can be used alone or in combination of two or more. From the viewpoint of improving moisture-proof performance, a dicarboxylic acid having a cyclohexane ring or a derivative thereof is preferred, more preferably at least one selected from 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and hydrogenated phthalic anhydride, and even more preferably hydrogenated phthalic anhydride.

[0045] The polyacid used as a raw material for the alicyclic polyester polyol (a1-1) may include polyacids other than alicyclic polyacids, provided that the function derived from the alicyclic polyester polyol (a1-1) is not impaired. From the viewpoint of exhibiting high moisture-proof performance, it is preferable to exclude polyacids other than alicyclic polyacids. The content of alicyclic polyacids in the polyacids used as raw materials for the alicyclic polyester polyol (a1-1) is preferably 99% by mass or more, and particularly preferably substantially 100% by mass.

[0046] From the viewpoint of obtaining excellent moisture-proof properties and adhesive strength, the number average molecular weight (Mn) of the alicyclic polyester polyol (a1-1) is preferably 500 to 10,000, more preferably 800 to 5,000. The number average molecular weight of the alicyclic polyester polyol (a1-1) is a value obtained by gel permeation chromatography (GPC) under the conditions described in the examples described later.

[0047] The alicyclic polyester polyol (a1-1) may have other structural units as long as it contains structural units derived from branched aliphatic diols and structural units derived from alicyclic polyacids, but it is preferably substantially composed only of structural units derived from branched aliphatic diols and structural units derived from alicyclic polyacids. The content of branched aliphatic diol-derived structural units in the alicyclic polyester polyol (a1-1) is preferably 85% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and particularly preferably substantially 100% by mass, based on the total amount of polyol-derived structural units in the alicyclic polyester polyol (a1-1). Furthermore, the content of alicyclic polyacid-derived structural units in the alicyclic polyester polyol (a1-1) is preferably 99% by mass or more, and particularly preferably substantially 100% by mass, based on the total amount of polyacid-derived structural units in the alicyclic polyester polyol (a1-1).

[0048] The alicyclic polyester polyol (a1-1) is obtained by polycondensation of an alicyclic polyacid and a branched aliphatic diol using existing known methods. The polycondensation reaction can be exemplified by the following method: the alicyclic polyacid and the branched aliphatic diol are placed in a reaction vessel, and high-boiling-point solvents such as xylene, esterification catalysts, polymerization inhibitors, etc., are added as needed, followed by dehydration condensation, thereby carrying out an esterification reaction. The reaction temperature of the polycondensation reaction is preferably in the range of 140℃ to 240℃, more preferably in the range of 170℃ to 230℃, and the reaction time is preferably in the range of 5 hours to 20 hours, more preferably in the range of 7 hours to 17 hours.

[0049] Examples of esterification catalysts include: metal oxides such as tin oxide, antimony oxide, titanium oxide, and vanadium oxide; Brønsted acids such as p-toluenesulfonic acid, sulfuric acid, and phosphoric acid; boron trifluoride complexes; Lewis acids such as titanium tetrachloride and tin tetrachloride; organometallic compounds such as calcium acetate, zinc acetate, manganese acetate, zinc stearate, alkyl tin oxide, and titanium alkoxide. One or more of these can be used individually or in combination. The amount of the esterification catalyst used is preferably in the range of 0.001% to 0.1% by mass relative to 100% by mass of the total mass of the alicyclic polyacid and the linear aliphatic diol, more preferably in the range of 0.005% to 0.03% by mass.

[0050] Examples of polymerization inhibitors include hydroquinone, monomethyl hydroquinone, o-methyl hydroquinone, di-tert-4-methylphenol, trimethyl hydroquinone, phenothiazine, and tert-butylcatechol. These can be used individually or in combination with two or more. The amount of the polymerization inhibitor used is preferably in the range of 0.001% to 0.3% by mass, more preferably in the range of 0.005% to 0.07% by mass, relative to 100% by mass of the total mass of the alicyclic polyacid and the linear aliphatic diol.

[0051] -Alicyclic polyester polyol (a1-2)-

[0052] The alicyclic polyester polyol (a1-2) has structural units derived from linear aliphatic diols and structural units derived from alicyclic polyacids. In other words, the alicyclic polyester polyol (a1-2) is a reaction product of a polyol with linear aliphatic diols as the main component and a polyacid with alicyclic polyacids as the main component, as essential raw materials. The alicyclic polyester polyol (a1-2) has two or more hydroxyl groups.

[0053] A straight-chain aliphatic diol is a compound having a structure in which a hydroxyl group is substituted on each of the two carbon atoms of a straight-chain aliphatic hydrocarbon, and which does not have side chains. Examples of such straight-chain 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 (dodecanoic acid), 1,11-undecanediol, 1,12-dodecanediol, 1,13-tetrazanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, 1,18-octadecanediol, 1,20-eicosanediol, etc.; and diols containing ether bonds such as diethylene glycol, triethylene glycol, dipropylene glycol, polytetramethylene glycol, polyethylene glycol, and polypropylene glycol, etc. These can be used individually or in combination with two or more.

[0054] The polyol used as a raw material for the alicyclic polyester polyol (a1-2) must contain a linear aliphatic diol, but the inclusion of polyols other than linear aliphatic diols is permitted as long as it does not impair the functionality derived from the alicyclic polyester polyol (a1-2). From the viewpoint of ensuring the physical properties exhibited by including the alicyclic polyester polyol (a1-2) and the effects brought about by the resin composition of this disclosure, the content of linear aliphatic diols in the polyol used as a raw material for the alicyclic polyester polyol (a1-2) is preferably 85% by mass or more, more preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably substantially 100% by mass.

[0055] As the alicyclic polyacids, specific compounds of the alicyclic polyacids used in the raw materials of the alicyclic polyester polyol (a1-1) can be listed. The alicyclic polyacids can be used alone or in combination of two or more. Details regarding the alicyclic polyacids in the alicyclic polyester polyol (a1-2) are the same as those regarding the alicyclic polyacids in the alicyclic polyester polyol (a1-1).

[0056] The polyacid used as a raw material for the alicyclic polyester polyol (a1-2) may include polyacids other than alicyclic polyacids, provided that the function derived from the alicyclic polyester polyol (a1-2) is not impaired. However, from the viewpoint of exhibiting high moisture-proof performance, it is preferable to exclude polyacids other than alicyclic polyacids. The content of alicyclic polyacids in the polyacids used as raw materials for the alicyclic polyester polyol (a1-2) is preferably 99% by mass or more, and particularly preferably substantially 100% by mass.

[0057] From the viewpoint of obtaining excellent moisture-proof properties and adhesive strength, the number average molecular weight (Mn) of the alicyclic polyester polyol (a1-2) is preferably in the range of 500 to 10,000, more preferably in the range of 800 to 5,000. The number average molecular weight of the alicyclic polyester polyol (a1-2) is a value obtained by gel permeation chromatography (GPC) under the conditions described in the examples described later.

[0058] The alicyclic polyester polyol (a1-2) may have other structural units as long as it contains structural units derived from linear aliphatic diols and structural units derived from alicyclic polyacids, but it is preferably substantially composed only of structural units derived from linear aliphatic diols and structural units derived from alicyclic polyacids. The content of linear aliphatic diol-derived structural units in the alicyclic polyester polyol (a1-2) is preferably 85% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and particularly preferably substantially 100% by mass, based on the total amount of polyol-derived structural units in the alicyclic polyester polyol (a1-2). Furthermore, the content of alicyclic polyacid-derived structural units in the alicyclic polyester polyol (a1-2) is preferably 99% by mass or more, and particularly preferably substantially 100% by mass, based on the total amount of polyacid-derived structural units in the alicyclic polyester polyol (a1-2).

[0059] The alicyclic polyester polyol (a1-2) is obtained by polycondensation of an alicyclic polyacid and a linear aliphatic diol using existing known methods. The polycondensation reaction can be exemplified by the following method: the alicyclic polyacid and the linear aliphatic polyol are loaded into a reaction vessel, and high-boiling-point solvents such as xylene, esterification catalysts, and polymerization inhibitors are added as needed, followed by dehydration condensation, thereby carrying out an esterification reaction. The reaction temperature and time of the polycondensation reaction, as well as the specific examples and amounts of the esterification catalyst and polymerization inhibitor used, can be set to be the same as those used in the preparation of the alicyclic polyester polyol (a1-1) for the polycondensation reaction.

[0060] -Alicyclic polyester polyol (a1)-

[0061] The content of the alicyclic polyester polyol (a1) in the polyol (A) (the total content of the alicyclic polyester polyol (a1-1) and the alicyclic polyester polyol (a1-2)) is preferably 50% by mass or more, possibly 55% by mass or more, or possibly 60% by mass or more, in 100% by mass of the polyol (A). Furthermore, while the upper limit of the content of the alicyclic polyester polyol (a1) in 100% by mass of the polyol (A) also depends on the content of other components, it is preferably 80% by mass or less. More specifically, the content of the alicyclic polyester polyol (a1) in 100% by mass of the polyol (A) is more preferably in the range of 50% by mass to 75% by mass, and even more preferably in the range of 50% by mass to 65% by mass. By setting the content of the alicyclic polyester polyol (a1) in the polyol (A) to the aforementioned range, the resin composition of this disclosure exhibits excellent moisture resistance and sprayability.

[0062] The alicyclic polyester polyol (a1) comprises at least one of the alicyclic polyester polyol (a1-1) and the alicyclic polyester polyol (a1-2). Preferably, it comprises at least the alicyclic polyester polyol (a1-1). By including the alicyclic polyester polyol (a1-1), the resin composition of this disclosure exhibits excellent moisture resistance and sprayability, and can also form a thin and more homogeneous coating film through spray application. The content of the alicyclic polyester polyol (a1) in the alicyclic polyester polyol (a1) is preferably 50% by mass or more, more preferably 55% by mass or more, and even more preferably 60% by mass or more. When the alicyclic polyester polyol (a1) comprises both alicyclic polyester polyol (a1-1) and alicyclic polyester polyol (a1-2), the content ratio of alicyclic polyester polyol (a1-1) to alicyclic polyester polyol (a1-2) [(a1-1) / (a1-2)] by mass is preferably in the range of 50 / 50 to 95 / 5, more preferably in the range of 55 / 45 to 90 / 10, and even more preferably in the range of 60 / 40 to 80 / 20. Because the contents of the alicyclic polyester polyol (a1-1) and the alicyclic polyester polyol (a1-2) have the aforementioned relationship, the resin composition of this disclosure exhibits excellent moisture resistance and sprayability, and in addition, can form a thin and more homogeneous coating film through spray application.

[0063] <<Crystallized Polyester Polyols (a2)>>

[0064] The polyol (A) comprises a crystalline polyester polyol (a2) other than the alicyclic polyester polyol (a1). By including the crystalline polyester polyol (a2) in polyol (A), the resin composition of this disclosure exhibits superior adhesive properties (initial bond strength and final bond strength). The crystalline polyester polyol (a2) may be used alone or in combination with two or more. Furthermore, the term "final bond strength" refers to the final bond strength of the moisture-curing polyurethane hot-melt resin composition after curing.

[0065] In this disclosure, "crystallization" means that the peak value of the heat of crystallization or heat of fusion can be confirmed in measurements using a differential scanning calorimeter (DSC) according to Japanese Industrial Standards (JIS) K7121:2012, and "amorphous" means that the peak value cannot be confirmed.

[0066] As the crystalline polyester polyol (a2), for example, crystalline polyester polyols containing structural units derived from aliphatic compounds having two or more hydroxyl groups and structural units derived from polyacids (a2-1), and crystalline polyester polyols containing structural units derived from alicyclic compounds having two or more hydroxyl groups and structural units derived from polyacids (a2-2), etc., can be used.

[0067] Furthermore, crystalline polyester polyols having structural units derived from alicyclic polyacids are not included in crystalline polyester polyols (a2), but are classified as alicyclic polyester polyols (a1) according to the type of structural unit from which the polyol originates. Additionally, the high molecular weight polycaprolactone polyol (a4), described later, is not included in crystalline polyester polyols (a2).

[0068] Crystalline polyester polyols containing structural units derived from aliphatic compounds having two or more hydroxyl groups and structural units derived from polybasic acids (a2-1) are reaction products of a polyol containing at least an aliphatic compound having two or more hydroxyl groups as a major component and a polybasic acid as an essential raw material. Additionally, crystalline polyester polyols containing structural units derived from alicyclic compounds having two or more hydroxyl groups and structural units derived from polybasic acids (a2-2) are reaction products of a polyol containing at least an alicyclic compound having two or more hydroxyl groups as a major component and a polybasic acid as an essential raw material.

[0069] Examples of aliphatic compounds having two or more hydroxyl groups include: ethylene glycol, propylene glycol, 1,3-propanediol (trimethylenediol), 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,2-heptanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol. 1,12-Dodecanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, neopentyl glycol, 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-2-butyl-1,3-propanediol, 2-methyl-1,8-octanediol, 2,4-diethyl-1,5-pentanediol, trimethylolethane, trimethylolpropane, pentaerythritol, etc. These can be used alone or in combination of two or more.

[0070] Examples of alicyclic compounds having two or more hydroxyl groups include cyclopentanediol, cyclohexanediol, cyclohexanediethanol, hydrogenated bisphenol A, and their alkyl oxide adducts. These can be used alone or in combination of two or more.

[0071] The polyols used as reaction raw materials for the crystalline polyester polyols (a2-1) and (a2-2) are permitted to include polyols other than aliphatic and / or alicyclic compounds having two or more hydroxyl groups, provided that the function derived from the crystalline polyester polyol (a2) is not impaired. The content of aliphatic and / or alicyclic compounds having two or more hydroxyl groups in the polyol is preferably 85% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably substantially 100% by mass.

[0072] The polyacids used as reactants for the crystalline polyester polyols (a2-1) and (a2-2) can be, for example, oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanoic acid, etc. These compounds can be used alone or in combination of two or more. Among these, for improving crystallinity and obtaining further superior adhesion, one or more compounds selected from the group consisting of succinic acid, adipic acid, sebacic acid, and dodecanoic acid are preferred.

[0073] From the viewpoint of crystallinity, the crystalline polyester polyol (a2) is preferably a crystalline polyester polyol (a2-1) whose main component is a structural unit derived from an aliphatic compound having two or more hydroxyl groups and a structural unit derived from a polyacid. More preferably, it is a crystalline polyester polyol (a2-1) substantially containing structural units derived from an aliphatic compound having two or more hydroxyl groups and a structural unit derived from a polyacid. Specifically, the content of the crystalline polyester polyol (a2-1) containing structural units derived from an aliphatic compound having two or more hydroxyl groups and structural units derived from a polyacid in the crystalline polyester polyol (a2) is preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably 100% by mass in 100% by mass of the crystalline polyester polyol (a2). By setting the content of the crystalline polyester polyol (a2-1) in the crystalline polyester polyol (a2) within the above range, the reduction in crystallinity caused by having an alicyclic structure can be suppressed.

[0074] The number-average molecular weight of the crystalline polyester polyol (a2) is preferably in the range of 500 to 10,000, more preferably in the range of 1,000 to 6,000. The number-average molecular weight of the crystalline polyester polyol (a2) is a value obtained by gel permeation chromatography (GPC) under the conditions described in the examples described later.

[0075] The content of the crystalline polyester polyol (a2) is preferably in the range of 10% to 30% by mass of 100% by mass of polyol (A), and more preferably in the range of 20% to 30% by mass. By setting the content of the crystalline polyester polyol (a2) in the polyol (A) within the above range, a good balance between initial curability and moisture resistance can be achieved. If the content is too high, it may sometimes cause a decrease in moisture resistance; if it is too low, it may sometimes cause a decrease in initial curability.

[0076] <<Aromatic Polyester Polyols (a3)>>

[0077] The polyol (A) may also include aromatic polyester polyols (a3) ​​other than polyester polyols (a1) and crystalline polyester polyols (a2). By including aromatic polyester polyols (a3) ​​in the polyol (A), the initial bond strength can be stabilized.

[0078] Examples of aromatic polyester polyols (a3) ​​include, for instance, aromatic polyester polyols (a3-1) containing structural units derived from aliphatic and / or alicyclic compounds having two or more hydroxyl groups and structural units derived from aromatic polyacids; and aromatic polyester polyols (a3-2) containing structural units derived from aromatic compounds having two or more hydroxyl groups and structural units derived from polyacids.

[0079] The aromatic polyester polyol (a3-1) comprising structural units derived from aliphatic and / or alicyclic compounds having two or more hydroxyl groups and structural units derived from aromatic polyacids is a reaction product in which at least aliphatic and / or alicyclic compounds having two or more hydroxyl groups and aromatic polyacids are required raw materials.

[0080] The aliphatic and / or alicyclic compound having two or more hydroxyl groups, which serves as a raw material for the aromatic polyester polyol (a3-1), may be configured to be the same as the aliphatic and / or alicyclic compound having two or more hydroxyl groups in the "crystalline polyester polyol (a2)".

[0081] The aromatic polyacids used as raw materials for the aromatic polyester polyol (a3-1) may include, for example, phthalic acid, isophthalic acid, terephthalic acid, phthalic anhydride, etc. These may be used alone or in combination of two or more.

[0082] The aromatic polyester polyol (a3-1) may contain structural units derived from aliphatic and / or alicyclic compounds having two or more hydroxyl groups and structural units derived from aromatic polyacids, or other structural units, but preferably substantially contains structural units derived from aliphatic and / or alicyclic compounds having two or more hydroxyl groups and structural units derived from aromatic polyacids. The content of structural units derived from aliphatic and / or alicyclic compounds having two or more hydroxyl groups in the aromatic polyester polyol (a3-1) is based on the total amount of polyol-derived structural units in the aromatic polyester polyol (a3-1), preferably 85% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and particularly preferably substantially 100% by mass. Furthermore, the content of the aromatic polyacid-derived structural units in the aromatic polyester polyol (a3-1) is based on the total amount of polyacid-derived structural units in the aromatic polyester polyol (a3-1), preferably 85% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably substantially 100% by mass.

[0083] The aromatic polyester polyol (a3-2) containing structural units derived from aromatic compounds having two or more hydroxyl groups and structural units derived from polybasic acids is a reaction product that uses at least two or more hydroxyl groups and polybasic acids as essential raw materials.

[0084] As a raw material for the aromatic polyester polyol (a3-2), the aromatic compound having two or more hydroxyl groups can be, for example, bisphenol A, bisphenol F, and their epoxide adducts (ethylene oxide, propylene oxide, butane oxide, etc.). One of these can be used alone, or two or more can be used in combination.

[0085] The polyacids used as raw materials for the aromatic polyester polyol (a3-2) may include aliphatic or alicyclic polyacids such as those exemplified as raw materials for the aromatic polyester polyol (a3-1), such as oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, pimelic acid, octanoic acid, decanoic acid, dodecanoic acid, eicosanoic acid, citraconic acid, itaconic acid, citraconic anhydride, and itaconic anhydride. These may be used alone or in combination of two or more.

[0086] The aromatic polyester polyol (a3-2) may contain other structural units as long as it contains structural units derived from aromatic compounds having two or more hydroxyl groups and structural units derived from polybasic acids, but it is preferred to substantially contain structural units derived from aromatic compounds having two or more hydroxyl groups and structural units derived from polybasic acids. The content of structural units derived from aromatic compounds having two or more hydroxyl groups in the aromatic polyester polyol (a3-2) is based on the total amount of polyol-derived structural units constituting the aromatic polyester polyol (a3-2), preferably 85% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and particularly preferably substantially 100% by mass.

[0087] From the viewpoints of achieving high and stable final bond strength and forming good melt viscosity, the number average molecular weight of the aromatic polyester polyol (a3) ​​is preferably in the range of 500 to 10,000, more preferably in the range of 1,000 to 5,000. The number average molecular weight of the aromatic polyester polyol (a3) ​​is a value obtained by gel permeation chromatography (GPC) under the conditions described in the examples described later.

[0088] The content of the aromatic polyester polyol (a3) ​​is preferably in the range of 10% to 30% by mass of 100% by mass of polyol (A), and more preferably in the range of 10% to 20% by mass. By setting the content of the aromatic polyester polyol (a3) ​​in polyol (A) within the aforementioned range, both the initial and final bond strengths can be high and stabilized. In addition, a low melt viscosity can be achieved, resulting in excellent sprayability. If the content is too high, the melt viscosity may become too high, reducing workability; if it is too low, the final bond strength may not be sufficiently expressed.

[0089] <<Other Polyols>>

[0090] The polyol (A) may also include other polyols besides the polyol mentioned above. Examples of such other polyols include polyacrylic acid polyols, polycarbonate polyols, polyether polyols, polybutadiene polyols, and polycaprolactone polyols other than the high molecular weight polycaprolactone polyol (a4) described later. These polyols may be used alone or in combination of two or more.

[0091] <<Polyol (A)>>

[0092] The polyol (A) may also contain high molecular weight polycaprolactone polyol (a4), but preferably the content of high molecular weight polycaprolactone polyol (a4) in the polyol (A) is low, and particularly preferably it is substantially non-existent. Specifically, the content of high molecular weight polycaprolactone polyol (a4) in the polyol (A) is preferably less than 10% by mass in 100% by mass of the polyol, more preferably 5% by mass or less, further preferably 3% by mass or less, further more preferably 1% by mass or less, and particularly preferably 0% by mass, that is, the polyol (A) does not contain high molecular weight polycaprolactone polyol (a4). By setting the content of high molecular weight polycaprolactone polyol (a4) in the polyol (A) to the aforementioned range, the sprayability of the resin composition of this disclosure can be further improved.

[0093] The term "high molecular weight polycaprolactone polyol (a4)" refers to a polycaprolactone polyol with a number average molecular weight of 30,000 or higher. More specifically, the number average molecular weight of the high molecular weight polycaprolactone polyol (a4) only needs to be 30,000 or higher, but can be 40,000 or higher, or 50,000 or higher. Furthermore, there is no particular upper limit to the number average molecular weight of the high molecular weight polycaprolactone polyol (a4), but it is generally set to be below 200,000 or below 100,000. The number average molecular weight of the high molecular weight polycaprolactone polyol (a4) is expressed as a value obtained by gel permeation chromatography (GPC) under the conditions described in the examples below.

[0094] As the high molecular weight polycaprolactone polyol (a4), examples include the reaction products of compounds having two or more hydroxyl groups with ε-caprolactone. Regarding compounds having two or more hydroxyl groups, examples include aliphatic and / or alicyclic compounds having two or more hydroxyl groups, and aromatic compounds having two or more hydroxyl groups, as described in the section on polyester polyols (a1) to polyester polyols (a3).

[0095] <Polyisocyanate (B)>

[0096] As the polyisocyanate (B) in this disclosure, for example, aromatic polyisocyanates such as polymethylene polyphenyl polyisocyanate, diphenylmethane diisocyanate (specifically 4,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, etc.), carbodiimide-modified diphenylmethane diisocyanate, phenyl diisocyanate, toluene diisocyanate, and naphthalene diisocyanate; and aliphatic or alicyclic polyisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylene diisocyanate, and tetramethylxylene diisocyanate. These can be used alone or in combination of two or more. Among them, aromatic polyisocyanates are preferred, and diphenylmethane diisocyanate is more preferred.

[0097] The amount of polyisocyanate (B) used is preferably in the range of 5% to 40% by mass of the total mass of the raw materials constituting the urethane prepolymer (i), and more preferably in the range of 10% to 30% by mass.

[0098] <Carbamate Prepolymer (i)>

[0099] The urethane prepolymer (i) in this disclosure is a reaction product of the polyol (A) and the polyisocyanate (B) and has isocyanate groups. The urethane prepolymer (i), by having isocyanate groups, can react with moisture present in the air or in a substrate coated with the urethane prepolymer to form a cross-linked structure.

[0100] The so-called urethane prepolymer (i) is "the reaction product of the polyol (A) and the polyisocyanate (B)", which can be any reaction product in which the polyol (A) and the polyisocyanate (B) are necessary reaction components. The reaction components may also include any components other than the polyol (A) and the polyisocyanate (B) without impairing the function of the resin composition disclosed herein.

[0101] The method for manufacturing the urethane prepolymer (i) can be a known method, for example, the following method: adding the polyol (A) dropwise into a reaction vessel containing the polyisocyanate (B) and heating it, and reacting under conditions where the isocyanate groups of the polyisocyanate (B) are in excess relative to the hydroxyl groups of the polyol (A).

[0102] Regarding the equivalent ratio (NCO / OH) of the isocyanate group (NCO) in the polyisocyanate (B) and the hydroxyl group (OH) in the polyol (A) during the manufacture of the urethane prepolymer (i), from the viewpoint of reducing unreacted polyisocyanate (B), achieving sprayability, high moisture resistance, and high adhesion to the substrate resulting from spray coating, the ratio is preferably in the range of 1.5 to 5.0, and more preferably in the range of 2.0 to 3.0.

[0103] From the viewpoint of achieving sprayability, high moisture resistance, and high adhesion to the substrate resulting from spray coating, the isocyanate group content (hereinafter referred to as "NCO%)" of the urethane prepolymer (i) is preferably in the range of 1% to 10% by mass, and more preferably in the range of 2% to 6% by mass. The NCO% of the urethane prepolymer (i) is expressed as a value determined by potentiometric titration according to JIS K 1603-1:2007.

[0104] From the viewpoint of achieving sprayability, high moisture resistance, and high adhesion to the substrate resulting from spray coating, the number average molecular weight of the urethane prepolymer (i) is preferably in the range of 5,000 to 500,000, more preferably in the range of 10,000 to 300,000.

[0105] <Moisture-curing polyurethane hot melt resin composition>

[0106] The moisture-curing polyurethane hot melt resin composition disclosed herein may contain only urethane prepolymer, or it may contain any other components besides urethane prepolymer. Examples of such arbitrary components include: adhesive agents, curing catalysts, plasticizers, stabilizers, dyes, pigments, fluorescent whitening agents, silane coupling agents, waxes, fillers (e.g., inorganic fillers such as layered silicates, metal powders, calcium carbonate, clay, carbon black, etc.), and thermoplastic resins. The content of these arbitrary components may be suitably selected within a range that does not impair the effects of the moisture-curing polyurethane hot melt resin composition disclosed herein.

[0107] The content of urethane prepolymer in the moisture-curing polyurethane hot-melt resin composition disclosed herein is preferably 60% by mass or more, and may be 70% by mass or more, 80% by mass or more, or 90% by mass or more. Furthermore, the content is preferably 100% by mass or less, and may be 99% by mass or less, or 95% by mass or less. By setting the content of the urethane prepolymer within the aforementioned range, sprayability, high moisture resistance, and high adhesion to the substrate resulting from spray coating can be achieved.

[0108] The moisture-curing polyurethane hot-melt resin composition disclosed herein preferably has a melt viscosity of 5 Pa or less at 120°C, more preferably 0.5 Pa or more and 3 Pa or less, and even more preferably 0.5 Pa or more and 2 Pa or less. Because the melt viscosity of the moisture-curing polyurethane hot-melt resin composition disclosed herein is within this range, it exhibits excellent sprayability and can be applied in thin layers. The melt viscosity at 120°C of the moisture-curing polyurethane hot-melt resin composition disclosed herein is a value obtained by heating and melting the moisture-curing polyurethane hot-melt resin composition at 120°C and measuring it using a cone-plate viscometer (manufactured by ICI).

[0109] One preferred form of the moisture-curing polyurethane hot melt resin composition disclosed herein (Form Example 1) is a moisture-curing polyurethane hot melt resin composition containing a urethane prepolymer (i) having an isocyanate group, wherein the urethane prepolymer (i) is a reaction product of a polyol (A) and a polyisocyanate (B), wherein the polyol (A) must at least include an alicyclic polyester polyol (a1), a crystalline polyester polyol (a2), and an aromatic polyester polyol (a3), and the content of the alicyclic polyester polyol (a1) in the polyol (A) is 50% by mass or more.

[0110] One preferred form of the moisture-curing polyurethane hot melt resin composition disclosed herein (Form Example 2) is a moisture-curing polyurethane hot melt resin composition containing a urethane prepolymer (i) having an isocyanate group, wherein the urethane prepolymer (i) is a reaction product of a polyol (A) and a polyisocyanate (B), wherein the polyol (A) must contain at least an alicyclic polyester polyol (a1), a crystalline polyester polyol (a2), and an aromatic polyester polyol (a3), wherein the content of the crystalline polyester polyol (a2) is 10% to 30% by mass, the content of the aromatic polyester polyol (a3) ​​is 10% to 30% by mass, and the content of the high molecular weight polycaprolactone polyol (a4) in the polyol (A) is less than 10% by mass.

[0111] One preferred form of the moisture-curing polyurethane hot melt resin composition disclosed herein (Form Example 3) is a moisture-curing polyurethane hot melt resin composition containing a urethane prepolymer (i) having an isocyanate group, wherein the urethane prepolymer (i) is a reaction product of a polyol (A) and a polyisocyanate (B), wherein the polyol (A) must at least include an alicyclic polyester polyol (a1), a crystalline polyester polyol (a2), and an aromatic polyester polyol (a3), wherein the content of the crystalline polyester polyol (a2) is 10% to 30% by mass, the content of the aromatic polyester polyol (a3) ​​is 10% to 30% by mass, and the melt viscosity of the moisture-curing polyurethane hot melt resin composition at 120°C is 5 Pa. Below s.

[0112] [II. Hardened material]

[0113] The cured product disclosed herein is formed by curing the moisture-curing polyurethane hot melt resin composition described in item "I. Moisture-curing polyurethane hot melt resin composition".

[0114] Examples of cured products disclosed herein include, for instance, a cured film formed by moisture curing a coating film onto which a moisture-curing polyurethane hot-melt resin composition, which has been applied using a desired method, is applied. The heating and melting temperature of the moisture-curing polyurethane hot-melt resin composition is not particularly limited, but may be set to, for example, 100°C to 140°C.

[0115] From the viewpoint of being able to achieve conformal coatings for protecting printed circuit boards or parts used in electronic devices, the coating method for the moisture-curing polyurethane hot melt resin composition after heating and melting in this disclosure is preferably a spray coating method.

[0116] Furthermore, the coating method for moisture-curing polyurethane hot melt resin compositions is not limited to spray coating. For example, known coating methods such as rod coating, applicator coating, scraper coating, doctor blade coating, roller coating, T-die coating, corner wheel coating, gravure coating, distributor coating, nozzle coating, inkjet printing, screen printing, and offset printing can be used.

[0117] The moisture-curing polyurethane hot melt resin composition is preferably prepared by drying and curing the coating film after application.

[0118] The thickness of the hardened material disclosed herein is not particularly limited, for example, it can be set to a range of 5 μm to 300 μm.

[0119] Examples of cured products of this disclosure include films, adhesive layers, and coating layers. Films, as one form of cured product of this disclosure, have excellent moisture resistance and are therefore suitable for applications such as conformal coatings for substrates like printed circuit boards and other substrates containing electrical or electronic components, weatherproof films used in solar cells, and adhesive films.

[0120] In addition, the hardened material disclosed herein can be used in various industrial applications such as automobiles, electronic devices, construction, and textiles.

[0121] [III. Coating Agent]

[0122] The coating agent disclosed herein contains the moisture-curing polyurethane hot melt resin composition described in item "I. Moisture-curing polyurethane hot melt resin composition". The coating agent disclosed herein is generally solvent-free, but may contain solvents such as water or organic solvents.

[0123] The coating agent disclosed herein can be used, for example, as a conformal coating agent. Specifically, it can be used to perform electrical insulation treatment on soldered electronic circuit boards to protect them from the effects of water, moisture, and dust.

[0124] [IV. Adhesives]

[0125] The adhesive disclosed herein contains the moisture-curing polyurethane hot melt resin composition described in item "I. Moisture-curing polyurethane hot melt resin composition". The adhesive disclosed herein is generally solvent-free, but may also contain solvents such as water or organic solvents.

[0126] The adhesive disclosed herein can also be formed into a film and used as an adhesive film. The adhesive film can be formed by coating the adhesive containing the moisture-curing polyurethane hot-melt resin composition described in item "I. Moisture-curing polyurethane hot-melt resin composition" onto a release substrate such as polyethylene terephthalate (PET) film and then drying it. The coating method of the adhesive disclosed herein can, for example, be the same as the coating method described in item "II. Cured material".

[0127] The thickness of the adhesive film can be set appropriately according to the application, and is therefore not limited, for example, it can be set to the range of 5 μm to 300 μm.

[0128] [V. Items]

[0129] The articles disclosed herein have at least a cured layer of the moisture-curing polyurethane hot melt resin composition described in item I, “Moisture-curing polyurethane hot melt resin composition”.

[0130] As an example of an embodiment of the articles disclosed herein, the following configuration can be cited: having a first adherend and a coating layer formed on at least one side of the first adherend by a cured product of the moisture-curing polyurethane hot-melt resin composition of the present disclosure. More specifically, an article can be cited comprising an electronic circuit board having electronic components on a substrate, and a coating layer disposed on and covering the electronic components. The coating layer can maintain the electrical insulation of the electronic components while providing long-term stable protection against contaminants such as water, dust, and metal powder.

[0131] As another example of an embodiment of the articles of this disclosure, the following configuration can be described: having at least a first adherend and an adhesive layer formed by a hardened product of a moisture-curing polyurethane hot-melt resin composition disposed on the first adherend. In this configuration, a second adherend may also be disposed on the adhesive layer, and the first and second adherends are bonded together through the adhesive layer.

[0132] Examples of the adhered materials include: substrates, films, sheets, etc. When the articles of this disclosure have two or more adhered materials, the first and second adhered materials may be the same or different. For example, one of the first and second adhered materials may be a substrate, and the other may be a film or sheet. Alternatively, one of the first and second adhered materials may be a resin substrate, and the other may be a substrate made of a material other than resin.

[0133] Examples of substrates include: fiber substrates, glass substrates, wood substrates, metal substrates, ceramic substrates, and resin substrates. More specifically, wood substrates such as plywood, medium-density fiberboard (MDF), and particleboard; metal substrates such as aluminum, iron, copper, nickel, and silicon; ceramic substrates such as aluminum nitride, alumina, and silicon carbide; fiber substrates such as nonwoven fabrics, woven fabrics, and braided fabrics formed from polyester fibers, polyethylene fibers, nylon fibers, acrylic fibers, polyurethane fibers, acetate fibers, rayon fibers, polylactic acid fibers, cotton, linen, silk, wool, glass fibers, carbon fibers, and blended fibers thereof; impregnated substrates formed by impregnating nonwoven fabrics with resins such as polyurethane resin; composite substrates in which a porous layer is further formed on the nonwoven fabric; paper; and resin substrates. The substrate can be a flat plate or have complex shapes such as grooves, R-sections, and reverse R-sections.

[0134] As the sheet or film, for example, sheets or films obtained using resins such as polyolefins, polyesters, polyamides, polystyrene, polycarbonates, vinyl chloride, ethylene-vinyl acetate copolymers, polyvinyl alcohol, and polypropylene, as well as paper, metal foils, and sheets, can be used. Alternatively, the sheet or film can also be a sheet or film with decorative solid or multicolored or patterned designs applied to its surface, commonly referred to as decorative paper, decorative board base paper, or decorative sheet. Furthermore, a primer coating treatment can be applied to the back of these sheets or films using resins or the like.

[0135] Furthermore, examples of the adhered material include components used in electronic devices or mounting substrates for those components. Specifically, examples include: printed wiring boards and other electronic device substrates (particularly electronic circuit boards or electronic circuit mounting substrates); semiconductor device substrates; semiconductor device substrates carrying semiconductor elements, etc., but are not limited to these. Materials used for substrates used in electronic devices or electronic materials (e.g., printed wiring boards) can include, for example: plastic substrates; metal substrates such as aluminum, copper, nickel, and silicon; ceramic substrates such as aluminum nitride, alumina, and silicon carbide; glass plates, and various other materials, selected appropriately according to the application.

[0136] The manufacturing method of the articles disclosed herein is not particularly limited, and the following method can be used: applying the moisture-curing polyurethane hot melt resin composition of this disclosure to the substrate using the coating method described in section "II. Cured Material", and then subjecting it to moisture curing. When the articles of this disclosure have two or more substrates, the moisture-curing polyurethane hot melt resin composition of this disclosure is applied to the first substrate, and the second substrate is adhered to the moisture-curing polyurethane hot melt resin composition. After pressing using methods such as roller pressing, flat pressing, or belt pressing, the moisture-curing polyurethane hot melt resin composition is dried and cured as needed, thereby manufacturing an article formed by bonding two substrates together with a cured product of the moisture-curing polyurethane hot melt resin composition of this disclosure.

[0137] In the method of manufacturing the article disclosed herein, it is preferable to spray-coat the substrate with the moisture-curing polyurethane hot melt resin composition. Because the moisture-curing polyurethane hot melt resin composition has excellent sprayability, a thin coating film can be formed.

[0138] Specifically, examples of items disclosed herein include: electronic components such as wiring boards, smartphones, input boards, and portable electronic devices such as watches. Other examples of items disclosed herein, depending on the type or purpose of the adhered material, include: building materials such as building panels and decorative panels; automotive interior materials; automotive parts; battery components; and electronic components such as wiring boards.

[0139] This disclosure is not limited to the described embodiments. The described embodiments are examples, and any embodiment having a structure that is substantially the same as the technical concept described in the claims of this disclosure and achieving the same effect is included within the technical scope of this disclosure.

[0140] [Example]

[0141] The present invention will now be described in more detail using examples and comparative examples.

[0142] [Method for determining number-average molecular weight]

[0143] The number-average molecular weight is the value obtained by gel permeation chromatography (GPC) under the following conditions.

[0144] Measurement apparatus: High-speed GPC device (HLC-8220GPC manufactured by Tosoh Corporation)

[0145] Tube Column: The following tube columns manufactured by Tosoh Corporation are connected in series for use.

[0146] "TSKgel G5000" (7.8 mmI.D. × 30 cm) × 1

[0147] "TSKgel G4000" (7.8 mm I.D. × 30 cm) × 1 piece

[0148] "TSKgel G3000" (7.8 mmI.D. × 30 cm) × 1

[0149] "TSKgel G2000" (7.8 mm I.D. × 30 cm) × 1 piece

[0150] Detector: Refractive index (RI) (differential refractometer)

[0151] Column temperature: 40℃

[0152] Eluent: Tetrahydrofuran (THF)

[0153] Flow rate: 1.0 mL / min

[0154] Injection volume: 100 μL (a tetrahydrofuran solution with a sample concentration of 0.4% by mass)

[0155] Standard sample: Calibration curves were prepared using the following standard polystyrene.

[0156] (Standard polystyrene)

[0157] "TSKgel Standard Polystyrene A-500" manufactured by Tosoh Corporation

[0158] "TSKgel Standard Polystyrene A-1000" manufactured by Tosoh Corporation

[0159] "TSKgel Standard Polystyrene A-2500" manufactured by Tosoh Corporation

[0160] "TSKgel Standard Polystyrene A-5000" manufactured by Tosoh Corporation

[0161] "TSKgel Standard Polystyrene F-1" manufactured by Tosoh Corporation

[0162] "TSKgel Standard Polystyrene F-2" manufactured by Tosoh Corporation

[0163] "TSKgel Standard Polystyrene F-4" manufactured by Tosoh Corporation

[0164] "TSKgel Standard Polystyrene F-10" manufactured by Tosoh Corporation

[0165] "TSKgel Standard Polystyrene F-20" manufactured by Tosoh Corporation

[0166] "TSKgel Standard Polystyrene F-40" manufactured by Tosoh Corporation

[0167] "TSKgel Standard Polystyrene F-80" manufactured by Tosoh Corporation

[0168] "TSKgel Standard Polystyrene F-128" manufactured by Tosoh Corporation

[0169] "TSKgel Standard Polystyrene F-288" manufactured by Tosoh Corporation

[0170] "TSKgel Standard Polystyrene F-550" manufactured by Tosoh Corporation

[0171] [Example 1] Moisture-curing polyurethane hot melt resin composition (PUR-A)

[0172] A mixture of 60 parts by weight of alicyclic polyester polyol (a1-2) (the reaction product of neopentyl glycol and hydrogenated phthalic anhydride, with a number average molecular weight of 2,000, referred to as "NPG / HHPA" in the table below), 30 parts by weight of crystalline polyester polyol (a2) (the reaction product of 1,6-hexanediol and dodecanoic acid, with a number average molecular weight of 3,500, referred to as "HG / DDA" in the table below), and 10 parts by weight of aromatic polyester polyol (a3) ​​(the reaction product of neopentyl glycol and phthalic anhydride, with a number average molecular weight of 1,000, referred to as "NPG / oPA" in the table below) was dried under reduced pressure at 110°C and dehydrated until the moisture content was below 0.05%. Subsequently, after cooling the dehydrated mixture to 90°C, 30 parts by weight of 4,4-methylene diisocyanate (hereinafter referred to as "MDI") are added, the temperature is raised to 120°C and reacted for 2 hours until the isocyanate group content is determined to prepare a urethane prepolymer, thereby obtaining a moisture-curing polyurethane hot melt resin composition (PUR-A).

[0173] [Example 2] Moisture-curing polyurethane hot melt resin composition (PUR-B)

[0174] Instead of 60 parts by mass of the alicyclic polyester polyol (a1-1) (the reaction product of 1,6-hexanediol and hydrogenated phthalic anhydride, quantity average molecular weight: 2,000, referred to as "HG / HHPA" in the table below), 60 parts by mass of the alicyclic polyester polyol (a1-2) were used to prepare a urethane prepolymer in the same manner as in Example 1, thereby obtaining a moisture-curing polyurethane hot melt resin composition (PUR-B).

[0175] [Comparative Example 1] Moisture-curing polyurethane hot melt resin composition (PUR-C)

[0176] The amount of alicyclic polyester polyol (a1-2) was set to 30 parts by mass, and the amount of aromatic polyester polyol (a3) ​​was set to 40 parts by mass. Otherwise, the urethane prepolymer was prepared in the same manner as in Example 1, thereby obtaining a moisture-curing polyurethane hot melt resin composition (PUR-C).

[0177] [Comparative Example 2] Moisture-curing polyurethane hot melt resin composition (PUR-D)

[0178] The amount of alicyclic polyester polyol (a1-2) was set to 30 parts by mass, the amount of crystalline polyester polyol (a2) was set to 50 parts by mass, the amount of aromatic polyester polyol (a3) ​​was set to 20 parts by mass, and the amount of 4,4-methylene diisocyanate was set to 35 parts by mass. Otherwise, the urethane prepolymer was prepared in the same manner as in Example 1 to obtain a moisture-curing polyurethane hot melt resin composition (PUR-D).

[0179] [Comparative Example 3] Moisture-curing polyurethane hot melt resin composition (PUR-E)

[0180] The amount of alicyclic polyester polyols (a1-2) was set to 50 parts by mass, and then 10 parts by mass of polycaprolactone polyol (a4) (number average molecular weight: 80,000, referred to as "PCL" in the table below) were added. Otherwise, the urethane prepolymer was prepared in the same manner as in Example 1, thereby obtaining a moisture-curing polyurethane hot melt resin composition (PUR-E).

[0181] [evaluate]

[0182] The moisture-curing polyurethane hot melt resin compositions obtained in the Examples and Comparative Examples were evaluated as follows. The results are shown in the table.

[0183] <Humidity permeability>

[0184] A release film containing polyethylene terephthalate was placed on a glass plate with the surface temperature adjusted to 100°C. After melting at 120°C, a moisture-curing polyurethane hot-melt resin composition was applied using a coater to a thickness of 100 μm. After curing for one week at 23°C and 50% relative humidity, the cured film, which is the moisture-curing polyurethane hot-melt resin, was peeled off from the release film to obtain a test sample. The moisture permeability of the test sample was determined and evaluated using the moisture permeability cup method (JIS Z0208 1976 B method).

[0185] (Evaluation Criteria)

[0186] T: 20 g / m 2 less than 24 hours

[0187] F: 20 g / m 2 greater than 24 hours

[0188] <Melt viscosity at 120℃>

[0189] A moisture-curing polyurethane hot melt resin composition was prepared as a coating agent. After being heated and melted at 120°C, the viscosity of the coating agent was measured using a cone-plate viscometer (manufactured by ICI).

[0190] <Spray compatibility>

[0191] A moisture-curing polyurethane hot melt resin composition was prepared as a coating agent. After being heated at 120°C, it was applied using a glue gun (Reka "TR-80LCD") at a coating weight of 100 g / m². 2 The coating agent is sprayed onto a steel plate, and the spray suitability is evaluated based on the condition of the coated surface and according to the following criteria.

[0192] A: No stringing was observed on the coated surface, resulting in a uniform and smooth coating surface.

[0193] B: No stringing was observed on the coated surface, but the uniformity and smoothness of the coated surface were slightly poor.

[0194] C: Stringing was observed on the coated surface, indicating poor uniformity and smoothness of the coating.

[0195] [Table 1]

[0196]

[0197] Based on the results, the moisture-curing polyurethane hot melt resin composition of the embodiments exhibits good spray adaptability, enabling the formation of a thin and highly moisture-resistant coating layer by spray coating. Specifically, Example 1 suggests that it is more effective than Example 2 in forming a coating film with a uniform and smooth surface.

[0198] On the other hand, the moisture-curing polyurethane hot melt resin compositions of Comparative Examples 1 and 3 exhibited stringing of the coating agent after spraying, resulting in unevenness on the coated surface and lacking sprayability. Furthermore, the moisture-curing polyurethane hot melt resin composition of Comparative Example 2 failed to achieve moisture resistance.

Claims

1. A moisture-curing polyurethane hot melt resin composition comprising a urethane prepolymer (i) having isocyanate groups, wherein the moisture-curing polyurethane hot melt resin composition, The urethane prepolymer (i) is a reaction product of polyol (A) and polyisocyanate (B). The polyol (A) must include at least alicyclic polyester polyol (a1), crystalline polyester polyol (a2), and aromatic polyester polyol (a3). The content of the alicyclic polyester polyol (a1) in the polyol (A) is 50% by mass or more.

2. A moisture-curing polyurethane hot melt resin composition comprising a urethane prepolymer (i) having isocyanate groups, wherein the moisture-curing polyurethane hot melt resin composition, The urethane prepolymer (i) is a reaction product of polyol (A) and polyisocyanate (B). The polyol (A) must include at least alicyclic polyester polyol (a1), crystalline polyester polyol (a2), and aromatic polyester polyol (a3). The content of the crystalline polyester polyol (a2) is 10% to 30% by mass. The content of the aromatic polyester polyol (a3) ​​is 10% to 30% by mass. The content of high molecular weight polycaprolactone polyol (a4) in the polyol (A) is less than 10% by mass.

3. A moisture-curing polyurethane hot melt resin composition comprising a urethane prepolymer (i) having isocyanate groups, wherein the moisture-curing polyurethane hot melt resin composition, The urethane prepolymer (i) is a reaction product of polyol (A) and polyisocyanate (B). The polyol (A) must include at least alicyclic polyester polyol (a1), crystalline polyester polyol (a2), and aromatic polyester polyol (a3). The content of the crystalline polyester polyol (a2) is 10% to 30% by mass. The content of the aromatic polyester polyol (a3) ​​is 10% to 30% by mass. The melt viscosity of the moisture-curing polyurethane hot melt resin composition at 120°C is 5 Pa. Below s.

4. The moisture-curing polyurethane hot melt resin composition according to any one of claims 1 to 3, wherein, The alicyclic polyester polyol (a1) comprises at least an alicyclic polyester polyol (a1-1) having structural units derived from branched aliphatic polyols and structural units derived from alicyclic polyacids.

5. The moisture-curing polyurethane hot melt resin composition according to claim 1, wherein, The content of high molecular weight polycaprolactone polyol (a4) in the polyol (A) is less than 10% by mass.

6. The moisture-curing polyurethane hot melt resin composition according to claim 1 or 2, wherein, The melt viscosity at 120℃ is 5 Pa. Below s.

7. A coating agent comprising a moisture-curing polyurethane hot melt resin composition as described in any one of claims 1 to 6.

8. An adhesive comprising a moisture-curing polyurethane hot melt resin composition as described in any one of claims 1 to 6.

9. A cured product, which is a cured product of the moisture-curing polyurethane hot melt resin composition as described in any one of claims 1 to 6.

10. An article having a cured form of the moisture-curing polyurethane hot melt resin composition as described in any one of claims 1 to 6.

11. An article having a cured form of the moisture-curing polyurethane hot melt resin composition as described in any one of claims 1 to 6 on an electronic circuit board.

12. A method of manufacturing an article, wherein a moisture-curing polyurethane hot melt resin composition as described in any one of claims 1 to 6 is spray-coated onto an object.

13. The method of manufacturing the article according to claim 12, wherein, The object to be adhered to is an electronic circuit board or an electronic component on the electronic circuit board.

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