Moisture-curing polyurethane hot melt resin composition, adhesive, and laminate

Abstract

Provided are a moisture-curable polyurethane hot melt resin composition, an adhesive, and a laminate, which are excellent in drop impact resistance and heat creep resistance. A moisture-curable polyurethane hot melt resin composition contains a urethane prepolymer (i) having an isocyanate group, the urethane prepolymer (i) being obtained using a polyol (A) and a polyisocyanate (B) as raw materials, and the ratio [E'(25) / E'(60)] of the storage modulus E'(25) at 25°C to the storage modulus E'(60) at 60°C of the cured product of the moisture-curable polyurethane hot melt resin composition is in the range of 1.0 to 10.0.

Description

Technical Field

[0001] This invention relates to moisture-curing polyurethane hot melt resin compositions. Background Technology

[0002] Moisture-curing polyurethane hot melt adhesives exhibit final bond strength through moisture curing of the isocyanate groups in the urethane prepolymer, which is the main component. Because they are solvent-free, they are used as environmentally friendly adhesives in various fields such as construction and electronic equipment.

[0003] For electronic devices such as smartphones and smartwatches, the adhesives used in joining components must be resistant to drop impacts to prevent parts from detaching in the event of an accidental drop. For example, Patent Document 1 discloses a moisture-curing polyurethane hot melt adhesive with excellent drop impact resistance.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-222776 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] In recent years, with the increasing performance of electronic terminals, the internal temperature of these terminals is prone to rise due to high-load operation and the internal heat generated by high-capacity batteries. Furthermore, this internal temperature rise can cause the moisture-curing polyurethane hot-melt adhesives used in the terminals to peel off easily due to heat exposure.

[0009] However, for moisture-curing polyurethane hot melt adhesives, it is not easy to obtain heat creep resistance if drop impact resistance is to be improved. On the other hand, if the heat creep resistance of moisture-curing polyurethane hot melt adhesives is to be improved, the flexibility is reduced and the drop impact resistance is poor. Therefore, it is difficult to achieve both drop impact resistance and heat creep resistance.

[0010] The present invention was made in view of the above-mentioned actual situation, and its purpose is to provide a moisture-curing polyurethane hot melt resin composition with excellent resistance to drop impact and heat creep.

[0011] Methods for solving problems

[0012] The present invention includes the following embodiments.

[0013] [1] A moisture-curing polyurethane hot melt resin composition containing a urethane prepolymer (i) having an isocyanate group, wherein the urethane prepolymer (i) is made from a polyol (A) and a polyisocyanate (B), and the ratio of the storage modulus E'(25) at 25°C to the storage modulus E'(60) at 60°C [E'(25) / E'(60)] of the cured product of the moisture-curing polyurethane hot melt resin composition is in the range of 1.0 to 10.0.

[0014] [2] According to the moisture-curing polyurethane hot melt resin composition described in [1] above, the storage modulus E'(60) of the cured product of the moisture-curing polyurethane hot melt resin composition at 60°C is in the range of 10MPa to 50MPa, and the storage modulus E'(25) of the cured product of the moisture-curing polyurethane hot melt resin composition at 25°C is in the range of 30MPa to 150MPa.

[0015] [3] According to the moisture-curing polyurethane hot melt resin composition described in [1] or [2] above, wherein the peak temperature of the loss tangent of the cured product of the moisture-curing polyurethane hot melt resin composition is below -15°C.

[0016] [4] The moisture-curing polyurethane hot melt resin composition according to any one of [1] to [3] above has a thixotropic index (TI) in the range of 1.11 to 1.80.

[0017] [5] The moisture-curing polyurethane hot melt resin composition according to any one of [1] to [4] above, wherein the polyol (A) comprises at least a polyether polyol (a1) and a polyacrylic acid polyol (a2).

[0018] [6] According to the moisture-curing polyurethane hot melt resin composition described above [5], wherein the polyether polyol (a1) comprises a high molecular weight polyether polyol, and the content of the high molecular weight polyether polyol is 10 to 50 parts by mass in 100 parts by mass of the raw material of the urethane prepolymer (i).

[0019] [7] According to the moisture-curing polyurethane hot melt resin composition described in [5] or [6] above, the content of the polyacrylic acid polyol (a2) is 3 to 20 parts by mass in 100 parts by mass of the raw material of the urethane prepolymer (i).

[0020] [8] The moisture-curing polyurethane hot melt resin composition according to any one of [1] to [7] above, wherein the polyol (A) further comprises at least one of polyester polyol (a3) ​​and polycarbonate polyol (a4).

[0021] [9] The moisture-curing polyurethane hot melt resin composition according to any one of [1] to [8] above, wherein the content of the polyisocyanate (B) is 10 to 40 parts by mass in 100 parts by mass of the raw material of the urethane prepolymer (i).

[0022]

[10] An adhesive comprising any of the above-mentioned moisture-curing polyurethane hot melt resin compositions [1] to [9].

[0023]

[11] A laminate having at least a substrate and a cured layer of the moisture-curing polyurethane hot melt resin composition described in any one of [1] to [9] above.

[0024] Invention Effects

[0025] The moisture-curing polyurethane hot melt resin composition of the present invention exhibits excellent resistance to drop impact and heat creep. Detailed Implementation

[0026] I. Moisture-curing polyurethane hot melt resin composition

[0027] The moisture-curing polyurethane hot melt resin composition of the present invention (hereinafter, sometimes simply referred to as "the composition of the present invention") contains a urethane prepolymer (i) having an isocyanate group, wherein the urethane prepolymer (i) is made from a polyol (A) and a polyisocyanate (B). Regarding the moisture-curing polyurethane hot melt resin composition of the present invention, the ratio of the storage modulus E'(25) of the cured product at 25°C to the storage modulus E'(60) at 60°C [E'(25) / E'(60)] is in the range of 1.0 to 10.0.

[0028] Regarding the resin composition of the present invention, the [E'(25) / E'(60)] of the cured resin composition is preferably in the range of 1.0 to 10.0, more preferably in the range of 1.2 to 9.5, even more preferably in the range of 1.2 to 9.0, further preferably in the range of 1.5 to 9.0, and even more preferably in the range of 1.5 to 8.0. The resin composition of the present invention, by having its cured [E'(25) / E'(60)] within the above-mentioned range, i.e., with a small difference between E'(25) and E'(60), can thereby possess both excellent drop impact resistance and excellent heat creep resistance.

[0029] Regarding the resin composition of the present invention, the storage modulus E'(25) of the cured resin composition at 25°C is preferably in the range of 30 MPa to 150 MPa, more preferably in the range of 35 MPa to 135 MPa, and even more preferably in the range of 40 MPa to 120 MPa. The resin composition of the present invention maintains adhesive strength and exhibits excellent drop impact resistance because the storage modulus E'(25) of the cured resin composition at 25°C is within the above-mentioned range.

[0030] Furthermore, regarding the resin composition of the present invention, the storage modulus E'(60) of the cured resin composition at 60°C is preferably in the range of 10 MPa to 50 MPa, more preferably in the range of 11 MPa to 45 MPa, and even more preferably in the range of 12 MPa to 40 MPa. The resin composition of the present invention exhibits excellent heat creep resistance because the storage modulus E'(60) of the cured resin composition at 60°C is within the above-mentioned range.

[0031] Regarding the resin composition of the present invention, the peak temperature of the loss tangent tanδ of the cured resin composition is preferably below -15°C, more preferably below -18°C, and even more preferably below -20°C. Because the peak temperature of the loss tangent tanδ of the cured resin composition of the present invention is within the above-mentioned range, the stress mitigation at room temperature is higher, resulting in superior drop impact resistance. Furthermore, the lower limit of the peak temperature of the loss tangent tanδ of the cured resin composition of the present invention is not particularly limited, but a lower value is preferred; for example, it is preferably above -70°C, more preferably above -50°C.

[0032] Regarding the storage modulus E'(25) and E'(60) of the cured product of the moisture-curing polyurethane hot melt resin composition at 25°C and 60°C, the moisture-curing polyurethane hot melt resin composition was heated and melted at 110°C, and then formed into a thickness of 100 μm using a roller coater. After being placed in a constant temperature and humidity bath at 23°C and 50%RH for 72 hours, a sheet of the cured product of the moisture-curing polyurethane hot melt resin composition with a thickness of 100 μm was produced. The storage modulus and loss tangent of the sheet were measured using a viscoelasticity measuring device (DMS6100 manufactured by SII NanoTechnology) under the following conditions. The storage modulus at 25°C at this time was set as E'(25) [MPa], and the storage modulus at 60°C at this time was set as E'(60) [MPa]. In addition, the temperature at which the loss tangent tanδ, as measured by the above method, reaches its peak position below 25°C is set as the peak temperature [°C] of the loss tangent tanδ of the cured resin composition.

[0033] (condition)

[0034] Temperature range: -100~200℃

[0035] Heating rate: 5℃ / minute

[0036] Frequency: 1Hz

[0037] Mode: Stretch mode

[0038] The thixotropic index (TI) of the resin composition of the present invention is preferably in the range of 1.11 to 1.80, more preferably in the range of 1.13 to 1.75, even more preferably in the range of 1.15 to 1.70, and may also be in the range of 1.20 to 1.65 or 1.25 to 1.60. The thixotropic index (TI) can be used as an indicator of compatibility. By ensuring that the thixotropic index (TI) of the resin composition of the present invention is within the above range, a significant phase separation state can be formed between soft segments such as polyols and hard segments such as isocyanates after moisture curing, thereby exhibiting both excellent drop impact resistance and excellent heat creep resistance.

[0039] The thixotropic index (TI) of the moisture-curing polyurethane hot melt resin composition was set to the thixotropic index (TI) at 110°C, and was as follows: A cone-plate viscometer CV-1 (manufactured by Toa Kogyo Co., Ltd.) was set to 110°C and heated. The moisture-curing polyurethane hot melt resin composition molten at 110°C was clamped between a cone and a plate, and the melt viscosity η5 and η6 were measured at rotor speeds of 5 rpm and 50 rpm. 50 The value is obtained by calculating using the following formula.

[0040] Thixotropic index (TI) = (melt viscosity at 5 rpm η5) / (melt viscosity at 50 rpm η) 50 )

[0041] The moisture-curing polyurethane hot melt resin composition of the present invention contains a urethane prepolymer (i) having isocyanate groups. The aforementioned urethane prepolymer (i) having isocyanate groups uses polyol (A) and polyisocyanate (B) as raw materials (constituent raw materials). In other words, the aforementioned urethane prepolymer (i) is a reaction product in which polyol (A) and polyisocyanate (B) are essential reactants. It should be noted that, to the extent that the effects of the moisture-curing polyurethane hot melt resin composition of the present invention are not impaired, components other than the aforementioned polyol (A) and polyisocyanate (B) are permitted in the raw materials (constituent raw materials) of the urethane prepolymer (i) and the aforementioned reaction product.

[0042] <<Polyols (A)>>

[0043] From the viewpoint that the resin composition of the present invention exhibits and maintains good drop impact resistance and heat creep resistance, and further demonstrates excellent adhesive strength, the aforementioned polyol (A) preferably comprises at least a polyether polyol (a1) and a polyacrylic acid polyol (a2). Preferably, in addition to the polyether polyol (a1) and the polyacrylic acid polyol (a2), the aforementioned polyol (A) also comprises at least one of a polyester polyol (a3) ​​and a polycarbonate polyol (a4). If it contains polyether polyol (a1) and polyacrylic acid polyol (a2), or polyester polyol (a3) ​​and polycarbonate polyol (a4), phase separation is easily formed, which is preferred from the viewpoint of possessing excellent combined high drop impact resistance, high heat creep resistance, and high adhesive strength.

[0044] <Polyether polyol (a1)>

[0045] The aforementioned polyether polyol (a1) is a polyol having oxyalkylene units in its main chain. Examples of the aforementioned polyether polyol (a1) include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyoxyethylene polyoxypropylene glycol, polyoxypropylene polyoxytetramethylene glycol, and polyoxypropylene triol. These can be used alone or in combination of two or more. From the viewpoint of improving the flexibility of the cured resin composition of the present invention and exhibiting excellent drop impact resistance, the aforementioned polyether polyol (a1) preferably contains one or more selected from polyethylene glycol, polypropylene glycol, and polyoxyethylene polyoxypropylene glycol. From the viewpoint of also providing superior adhesive strength in addition to flexibility and drop impact resistance, it is preferable to contain at least polyoxyethylene polyoxypropylene glycol, and more preferably polypropylene glycol and polyoxyethylene polyoxypropylene glycol.

[0046] The aforementioned polyoxyethylene polyoxypropylene glycol is a polyether polyol containing polyoxyethylene and polyoxypropylene groups. By using polyoxyethylene polyoxypropylene glycol as the polyether polyol (a1), the cured product (cured film) is softened, which can improve its resistance to drop impact and its adhesion.

[0047] The aforementioned polyoxyethylene polyoxypropylene glycol can be manufactured, for example, by addition polymerization of an initiator containing a compound having two or more active hydrogen atoms with alkyl oxidants, including ethylene oxide and propylene oxide. Specifically, it can be manufactured by mixing the aforementioned alkyl oxidants together or separately and mixing them in the presence of the aforementioned initiator to allow them to react.

[0048] For example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylolpropane, etc., can be used as the aforementioned initiators. In addition to ethylene oxide and propylene oxide, butane oxide can also be used in combination as needed.

[0049] The molar ratio of oxyethylidene (EO) to oxypropylene (PO) in the above-mentioned polyoxyethylidene polyoxypropylene glycol [EO / PO] is preferably in the range of 5 / 95 to 90 / 10, and more preferably in the range of 5 / 95 to 50 / 50.

[0050] Regarding the average number of functional groups (hydroxyl groups) of the aforementioned polyoxyethylene polyoxypropylene glycol, it is preferably in the range of 1.5 to 3.0, and more preferably in the range of 1.5 to 2.5.

[0051] The number average molecular weight of the polyether polyol (a1) is preferably in the range of 500 to 10,000, more preferably in the range of 750 to 9,000, and even more preferably in the range of 1,000 to 8,000. Preferably, the polyether polyol (a1) comprises a polyether polyol with a number average molecular weight of 3,000 or more (hereinafter also referred to as a high molecular weight polyether polyol). By including a high molecular weight polyether polyol in the polyether polyol (a1), the drop impact resistance of the cured resin composition of the present invention can be improved. The number average molecular weight of the high molecular weight polyether polyol is preferably in the range of 3,000 to 10,000, more preferably in the range of 3,500 to 9,000, and even more preferably in the range of 4,000 to 8,000.

[0052] The number-average molecular weights of the polyether polyols (a1) described above are values ​​obtained by gel permeation chromatography (GPC). The determination conditions were set as shown in the examples described later.

[0053] Regarding the amount of polyether polyol (a1) used, it is preferably in the range of 10 to 55 parts by mass of the raw material constituting the urethane prepolymer (i) out of 100 parts by mass, more preferably in the range of 15 to 50 parts by mass, and even more preferably in the range of 20 to 45 parts by mass. Of the polyether polyol (a1) used, the high molecular weight polyether polyol is preferably in the range of 10 to 50 parts by mass of the high molecular weight polyether polyol in the raw material constituting the urethane prepolymer (i) out of 100 parts by mass, more preferably in the range of 12 to 45 parts by mass, and even more preferably in the range of 14 to 40 parts by mass. It can also be in the range of 15 to 40 parts by mass, or in the range of 20 to 35 parts by mass. By setting the amount of high molecular weight polyether polyol in the raw material constituting the urethane prepolymer (i) within the above range, the drop impact resistance of the resin composition of the present invention can be further improved.

[0054] Regarding the content of the polyether polyol (a1) in the polyol (A), it is preferably in the range of 15% to 60% by mass in the total amount (100% by mass) of the polyol (A), more preferably in the range of 20% to 55% by mass, and even more preferably in the range of 25% to 50% by mass.

[0055] Furthermore, regarding the proportion of high molecular weight polyether polyol in the aforementioned polyether polyol (a1), as long as the amount of high molecular weight polyether polyol in the raw materials constituting the urethane prepolymer (i) falls within the aforementioned range, it is acceptable. Within the total amount of the aforementioned polyether polyol (a1) of 100% by mass, a range of 40% to 100% by mass is preferred, a range of 45% to 90% by mass is more preferred, and a range of 50% to 80% by mass is even more preferred. By setting the amount of high molecular weight polyether polyol in the polyether polyol (a1) within the aforementioned range, adhesive strength can be maintained, and excellent drop impact resistance can be achieved.

[0056] <Polyacrylate polyols (a2)>

[0057] The aforementioned polyacrylic acid polyol (a2) can, for example, be a polymer of a (meth)acrylic acid compound that must contain a (meth)acrylic acid compound having hydroxyl groups. It should be noted that, in this invention, "(meth)acrylic acid compound" refers to one or both of a methacrylic acid compound and an acrylic acid compound, and "(meth)acrylate" refers to one or both of a methacrylate and an acrylic acid ester.

[0058] Examples of hydroxyl-containing (meth)acrylic acid compounds include 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate (2-HBA), 3-hydroxypropyl methacrylate (3-HPA), and 4-hydroxybutyl methacrylate (4-HBA). These compounds can be used alone or in combination of two or more. 2-hydroxyethyl methacrylate is preferred as one of the hydroxyl-containing (meth)acrylic acid compounds described above.

[0059] Other (meth)acrylic acid compounds besides the aforementioned (meth)acrylic acid compounds containing hydroxyl groups may include, for example, (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, neopentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, cetyl (meth)acrylate, lauryl (meth)acrylate, and other alkyl (meth)acrylate esters; 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, 1H,1H,5H-octafluoropentyl (meth)acrylate, etc. The compounds include (meth)acrylic acid compounds with fluorine atoms, such as 2-(perfluorooctyl)ethyl acrylate; (meth)acrylic acid compounds with alicyclic structures, such as isobornyl methacrylate, cyclohexyl methacrylate, dicyclopentyl methacrylate, and dicyclopentenyloxyethyl methacrylate; (meth)acrylic acid compounds with ether groups, such as polyethylene glycol mono(meth)acrylate, methoxyethyl methacrylate, methoxybutyl methacrylate, methoxytriethylene glycol (meth)acrylate, and methoxypolyethylene glycol (meth)acrylate; and (meth)acrylic acid compounds such as benzyl methacrylate, 2-ethyl-2-methyl-[1,3]-dioxolane-4-yl-methyl(meth)acrylate, and dimethylaminoethyl methacrylate. These compounds can be used alone or in combination of two or more. Among these, alkyl methacrylates are preferred, and methyl methacrylates and / or n-butyl methacrylates are more preferred, from the perspective of obtaining even better adhesion and drop impact resistance.

[0060] From the perspective of obtaining even better drop impact resistance and adhesion, the number average molecular weight of the above-mentioned acrylic polyol (a2) is preferably in the range of 5,000 to 100,000, more preferably in the range of 10,000 to 30,000. The number average molecular weight of the above-mentioned acrylic polyol (a2) represents the value obtained by gel permeation chromatography (GPC). The measurement conditions are set as described in the examples below.

[0061] From the perspective of obtaining further superior drop impact resistance and adhesion, the glass transition temperature of the aforementioned acrylic polyol (a2) is preferably in the range of 40°C to 120°C, and more preferably in the range of 50°C to 90°C. The glass transition temperature of the aforementioned acrylic polyol (a2) is expressed as a value obtained by DSC measurement according to JIS K7121-1987. Specifically, it is expressed as the glass transition temperature (Tmg) at the midpoint of the obtained differential thermal curve, obtained by placing the aforementioned polyacrylic polyol (a2) in a differential scanning calorimeter and heating it to (Tg+50°C) at a heating rate of 10°C / min, holding it for 3 minutes, and then rapidly cooling it.

[0062] Regarding the amount of acrylic polyol (a2) used, from the perspective of obtaining even better drop impact resistance and adhesion, the preferred amount of 100 parts by weight of the raw material constituting the urethane prepolymer (i) is 3 to 20 parts by weight, more preferably 4 to 18 parts by weight, and even more preferably 5 to 15 parts by weight. The above-mentioned amount may also be in the range of 5 to 20 parts by weight, 7 to 18 parts by weight, or 10 to 15 parts by weight.

[0063] Regarding the content of the acrylic polyol (a2) in the polyol (A), from the viewpoint of obtaining even better drop impact resistance and adhesion, the total amount of polyol (A) (100% by mass) is preferably in the range of 3% to 35% by mass, more preferably in the range of 4% to 30% by mass, and even more preferably in the range of 5% to 25% by mass.

[0064] <Polyester Polyol (a3)>

[0065] In terms of achieving better cohesiveness and adhesion, the polyol (A) mentioned above preferably includes polyester polyol (a3).

[0066] The aforementioned polyester polyol (a3) ​​can be crystalline or amorphous, and can also combine crystalline and amorphous polyester polyols. From the viewpoint of suppressing foaming during moisture curing, the aforementioned polyester polyol (a3) ​​preferably comprises a crystalline polyester polyol. In this invention, "crystalline" refers to a property in which peaks of heat of crystallization or heat of fusion can be confirmed in DSC (differential scanning calorimetry) measurements according to JIS K7121:2012, and "amorphous" refers to a property in which the aforementioned peaks cannot be confirmed.

[0067] The aforementioned polyester polyol (a3) ​​preferably contains a crystalline polyester polyol with a melting point of 53°C or higher under the second run of a DSC (differential scanning calorimeter) (hereinafter, sometimes referred to as a highly crystalline polyester polyol). The melting point of the highly crystalline polyester polyol under the second run of a DSC is preferably 53°C or higher, and more preferably in the range of 55°C to 100°C, and more preferably in the range of 60°C to 80°C. The melting point and crystallinity of the crystalline polyester polyol can be adjusted by selecting the raw material monomers, copolymer composition, average molecular weight, etc.

[0068] Regarding the proportion of crystalline polyester polyol in the aforementioned polyester polyol (a3), it is preferably in the range of 30% to 100% by mass, more preferably in the range of 40% to 100% by mass, and even more preferably in the range of 50% to 100% by mass. By setting the proportion of crystalline polyester polyol in polyester polyol (a3) ​​within the above range, the cured resin composition of the present invention exhibits good adhesive strength (normal strength). Specifically, regarding the proportion of highly crystalline polyester polyol in the aforementioned polyester polyol (a3), it is preferably in the range of 5% to 70% by mass, more preferably in the range of 7% to 60% by mass, and even more preferably in the range of 9% to 50% by mass. By setting the proportion of highly crystalline polyester polyol in the aforementioned polyester polyol (a3) ​​within the above range, the adhesive strength of the cured resin composition of the present invention is improved, and heat creep resistance and drop impact resistance are maintained. It should be noted that the proportion of the above-mentioned highly crystalline polyester polyols can also be in the range of 5% to 100%, 10% to 80%, or 15% to 60% of 100% by mass in polyester polyol (a3).

[0069] The aforementioned polyester polyols (a3) ​​may be, for example, the reaction products (condensates) of compounds with hydroxyl groups and polybasic acids; polycaprolactone polyols, etc.

[0070] As the aforementioned compounds containing hydroxyl groups, compounds having two or more hydroxyl groups are preferred, such as ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, heptahydrate, octanediol, nonanediol, decanediol, trimethylolpropane, trimethylolethane, glycerol, etc. These compounds can be used alone or in combination of two or more. Among these, from the perspective of improving crystallinity and obtaining further superior adhesion, one or more compounds selected from butanediol, hexanediol, octanediol, and decanediol are preferred.

[0071] Examples of the aforementioned polyacids include oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, and dodecanoic acid. These compounds can be used alone or in combination of two or more. Among these, from the perspective of improving crystallinity and obtaining even better adhesion, one or more of succinic acid, adipic acid, sebacic acid, and dodecanoic acid are preferred.

[0072] As the polycaprolactone polyol mentioned above, for example, the reaction product of the above-mentioned compound having two or more hydroxyl groups and ε-caprolactone can be used.

[0073] In polyester polyols (a3), for highly crystalline polyester polyols, there are no particular limitations on the combination of polyol and polyacid as long as the melting point at the 2nd run of the DSC (differential scanning calorimeter) is within the above range. Examples of such compounds include the following compounds.

[0074] Condensates of ethylene glycol and sebacic acid with a number average molecular weight of 3000 or higher

[0075] Condensation products of 1,3-propanediol and sebacic acid with a number average molecular weight of 3500 or higher

[0076] Condensation products of 1,4-butanediol and sebacic acid with a number average molecular weight of 3500 or higher

[0077] Condensates of 1,6-hexanediol and sebacic acid with a number average molecular weight of over 3000

[0078] Condensates of 1,6-hexanediol and dodecanoic acid with a number average molecular weight of 3000 or higher

[0079] Condensations of 1,6-hexanediol and adipic acid with a number average molecular weight of 4000 or higher

[0080] Condensation products of 1,4-butanediol and adipic acid with a number average molecular weight of over 4000

[0081] It should be noted that highly crystalline polyester polyols are not limited to these exemplified compounds.

[0082] From the perspective of obtaining even better adhesion, the number average molecular weight of the above-mentioned polyester polyol (a3) ​​is preferably in the range of 500 to 10,000, more preferably in the range of 1,000 to 6,000. Among these, the number average molecular weight of the highly crystalline polyester polyol is preferably in the range of 3,000 to 8,500, more preferably in the range of 3,500 to 6,000. The number average molecular weight of the above-mentioned polyester polyol (a3) ​​represents the value obtained by gel permeation chromatography (GPC). The measurement conditions are set as described in the examples below.

[0083] The amount of the aforementioned polyester polyol (a3) ​​used is 0% by mass or more in 100 parts by mass of the raw materials constituting the urethane prepolymer (i). From the perspective of obtaining even better adhesive properties from the resin composition of the present invention, the amount used is preferably in the range of 5 to 50 parts by mass in 100 parts by mass of the raw materials constituting the urethane prepolymer (i), more preferably in the range of 10 to 40 parts by mass. The amount of crystalline polyester polyol used, particularly highly crystalline polyester polyol, is preferably 15 parts by mass or less in 100 parts by mass of the raw materials constituting the urethane prepolymer (i), preferably in the range of 1.5 to 15 parts by mass, more preferably in the range of 3 to 10 parts by mass. By setting the amount of highly crystalline polyester polyol to the above range, the resin composition of the present invention, in addition to having good drop impact resistance and heat creep resistance, also sufficiently suppresses foaming during moisture curing, thus further improving adhesive strength. If too much highly crystalline polyester polyol is used, the drop impact resistance and heat creep resistance of the resin composition of the present invention may sometimes decrease.

[0084] Regarding the content of the polyester polyol (a3) ​​in the polyol (A), it is 0% or more in the total amount of polyol (A) (100% by mass). From the viewpoint of obtaining even better adhesion, it is preferably in the range of 11% to 55% in the total amount of polyol (A) (100% by mass), more preferably in the range of 13% to 50% by mass, and even more preferably in the range of 15% to 45% by mass.

[0085] <Polycarbonate polyols (a4)>

[0086] From the viewpoint that the resin composition of the present invention facilitates phase separation and further improves thixotropy and heat creep resistance, the polyol (a) preferably comprises a polycarbonate polyol (a4). The polycarbonate polyol (a4) may, for example, be a reaction product of a compound having two or more hydroxyl groups with a carbonate and / or a carbonate chloride.

[0087] As compounds having two or more hydroxyl groups, examples include propylene glycol, butanediol, pentanediol, hexanediol, decanediol, caprolactone, cyclohexanediol, 3-methyl-1,5-pentanediol, neopentanediol, isosorbide, etc. These compounds can be used alone or in combination of two or more.

[0088] Examples of the aforementioned carbonates include dimethyl carbonate, diethyl carbonate, diphenyl carbonate, ethylene carbonate, and propylene carbonate. These compounds can be used alone or in combination of two or more.

[0089] The aforementioned polycarbonate polyol (a4) can be crystalline or amorphous, and can also be a combination of crystalline and amorphous polycarbonate polyols. From the viewpoint of suppressing foaming during moisture curing, it is preferable to include a crystalline polycarbonate polyol.

[0090] Furthermore, the aforementioned polycarbonate polyol (a4) can be either liquid or solid at room temperature. In this invention, "liquid at room temperature" means that the aforementioned polycarbonate polyol (a4) exhibits a fluid, liquid, or viscous state at 23°C.

[0091] From the perspective of obtaining even better adhesion, the number average molecular weight of the polycarbonate polyol (a4) is preferably in the range of 500 to 10,000, more preferably in the range of 700 to 4,000. The number average molecular weight of the polycarbonate polyol (a4) is expressed as a value determined by gel permeation chromatography (GPC). The determination conditions are set as described in the examples below.

[0092] The amount of polycarbonate polyol (a4) used is 0% by mass or more in 100 parts by mass of the raw materials constituting the urethane prepolymer (i). From the perspective of improving the thixotropic properties of the resin composition of the present invention and obtaining even more superior heat creep resistance, the amount used is preferably in the range of 3 to 30 parts by mass in 100 parts by mass of the raw materials constituting the urethane prepolymer (i), more preferably in the range of 5 to 27 parts by mass, and even more preferably in the range of 7 to 24 parts by mass. It should be noted that the amount of polycarbonate polyol (a4) used in 100 parts by mass of the raw materials constituting the urethane prepolymer (i) may also be in the range of 5 to 30 parts by mass, 10 to 27 parts by mass, or 15 to 24 parts by mass.

[0093] Regarding the content of the polycarbonate polyol (a4) in the polyol (A) mentioned above, it is 0% by mass or more. From the viewpoint of obtaining even better adhesion, the total amount (100% by mass) of the polyol (A) is preferably in the range of 0% to 35% by mass, more preferably in the range of 5% to 30% by mass, and even more preferably in the range of 10% to 25% by mass.

[0094] Other polyols

[0095] The aforementioned polyol (A) may also be used in combination with other polyols as needed. Examples of these other polyols include polybutadiene polyols and dimer diols. These polyols may be used alone or in combination of two or more.

[0096] <Polyol (A)>

[0097] Regarding the total content of polyether polyol (a1) and polyacrylic acid polyol (a2) in the total amount of the above polyol (A), it can be set to a range of 30% to 100% by mass in 100% of the total amount of polyol (A), preferably a range of 30% to 90% by mass, and more preferably a range of 40% to 80% by mass.

[0098] Regarding the total proportion of crystalline polyols in the total amount of polyol (A), it is preferably in the range of 10 to 70 parts by mass, preferably in the range of 10 to 60 parts by mass, preferably in the range of 15 to 60 parts by mass, and preferably in the range of 15 to 50 parts by mass, out of a total of 100 parts by mass of polyol (A).

[0099] In the 100 parts by weight of raw materials constituting the above-mentioned urethane prepolymer (i), the amount (total content) of the above-mentioned polyol (A) is not particularly limited as long as it can exert the effect of the resin composition of the present invention. For example, in the 100 parts by weight of raw materials constituting the urethane prepolymer (i), the amount of the above-mentioned polyol (A) can be 50 parts by weight or more, preferably 60 parts by weight or more, more preferably 65 parts by weight or more, and even more preferably 70 parts by weight or more. In addition, the upper limit of the amount (total content) of polyol (A) in the urethane prepolymer (i) is not particularly limited as long as it can exert the effect of the resin composition of the present invention. For example, it can be 90 parts by weight or less, preferably 85 parts by weight or less, and more preferably 80 parts by weight or less.

[0100] <<Polyisocyanates (B)>>

[0101] As the aforementioned polyisocyanate (B), for example, aromatic polyisocyanates such as polymethylene polyphenyl polyisocyanate, diphenylmethane diisocyanate, 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, phenylmethylene diisocyanate, and tetramethylphenylmethylene diisocyanate. Among these, aromatic polyisocyanates are preferred from the perspective of obtaining further superior reactivity and adhesion, and diphenylmethane diisocyanate is more preferred.

[0102] From the viewpoint of improving the drop impact resistance and heat creep resistance of the resin composition of the present invention, the amount of polyisocyanate (B) used is preferably in the range of 10 parts by weight to 40 parts by weight of the raw material constituting the urethane prepolymer (i) in 100 parts by weight, more preferably in the range of 13 parts by weight to 35 parts by weight, more preferably in the range of 15 parts by weight to 35 parts by weight, even more preferably in the range of 15 parts by weight to 30 parts by weight, and even more preferably in the range of 20 parts by weight to 30 parts by weight. If too much polyisocyanate (B) is used, it is difficult to obtain drop impact resistance; if too little is used, it is difficult to obtain heat creep resistance.

[0103] <<Carbamate Prepolymer (i)>>

[0104] Regarding the above-mentioned urethane prepolymer (i), it can be obtained by reacting the above-mentioned polyol (A) with the above-mentioned polyisocyanate (B). The above-mentioned urethane prepolymer (i) has isocyanate groups at the polymer ends and within the molecule. These isocyanate groups can react with moisture present in the air in the shell or adhered material coated with the above-mentioned urethane prepolymer to form a cross-linked structure.

[0105] The method for manufacturing the above-mentioned urethane prepolymer (i) is not limited. For example, it can be manufactured by adding the above-mentioned polyol (A) dropwise into a reaction vessel containing the above-mentioned polyisocyanate (B) and heating it, and reacting under the condition that the isocyanate groups of the above-mentioned polyisocyanate (B) are in excess relative to the hydroxyl groups of the above-mentioned polyol (A).

[0106] From the perspective of obtaining further superior drop impact resistance, heat creep resistance, and adhesion, the isocyanate group content (hereinafter referred to as "NCO%") of the above-mentioned urethane prepolymer (i) is preferably in the range of 1.5% by mass to 7% by mass, more preferably in the range of 1.8% by mass to 5% by mass. The NCO% of the above-mentioned urethane prepolymer (i) represents the value determined by potentiometric titration according to JIS K1603-1:2007.

[0107] The aforementioned urethane prepolymer (i) uses the aforementioned polyol (A) and the aforementioned polyisocyanate (B) as essential raw materials, but may also contain any other raw materials as needed. In the raw materials constituting the aforementioned urethane prepolymer (i) (100% by mass), the total content of the aforementioned polyol (A) and the aforementioned polyisocyanate (B) is preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably 100% by mass.

[0108] <<Moisture-curing polyurethane hot melt resin composition>>

[0109] The moisture-curing polyurethane hot melt resin composition of the present invention uses the above-mentioned urethane prepolymer (i) as an essential component, but may also contain other additives as needed. Examples of such other additives include antioxidants, tackifiers, plasticizers, stabilizers, fillers, dyes, pigments, fluorescent whitening agents, silane coupling agents, waxes, etc. These additives may be used alone or in combination of two or more.

[0110] Regarding the moisture-curing polyurethane hot melt resin composition of the present invention, the content of the urethane prepolymer (i) in the total amount (100% by mass) of the moisture-curing polyurethane hot melt resin composition may be 50% or more by mass, 60% or more by mass, or 70% or more by mass, and may also be 100% or less by mass, 99% or less by mass, 95% or less by mass, 90% or less by mass, or 80% or less by mass. The moisture-curing polyurethane hot melt resin composition of the present invention preferably contains urethane prepolymer (i) as a main component, but may also contain only urethane prepolymer (i).

[0111] The moisture-curing polyurethane hot melt resin composition of the present invention is particularly suitable for use as an adhesive in the assembly of electronic materials.

[0112] II. Adhesive

[0113] The adhesive of the present invention contains the moisture-curing polyurethane hot melt resin composition of the present invention. Details regarding the moisture-curing polyurethane hot melt resin composition contained in the adhesive of the present invention are as described in section "I. Moisture-curing polyurethane hot melt resin composition" above.

[0114] III. Laminated structures

[0115] The laminate of the present invention has at least a substrate and a cured layer of the moisture-curing polyurethane hot melt resin composition of the present invention.

[0116] Examples of suitable substrates include acrylic resins, urethane resins, silicone resins, epoxy resins, fluorinated resins, polystyrene resins, polyester resins, polysulfone resins, polyarylate resins, polyvinyl chloride resins, polyvinylidene chloride resins, cycloolefin resins, polyolefin resins, polyimide resins, alicyclic polyimide resins, cellulose resins, PC (polycarbonate), PBT (polybutylene terephthalate), modified PPE (polyphenylene ether), PEN (polyethylene naphthalate), PET (polyethylene terephthalate), lactic acid polymers, ABS resins, AS resins, and other resin films; wood-based substrates such as MDF, plywood, and particleboard; fiber-based substrates such as non-woven fabrics, woven fabrics, and braided fabrics; and metal-based substrates such as stainless steel, aluminum, copper, steel, chromium, zinc, duralumin, die-casting molds, and their alloys. These substrates can also be subjected to surface treatments such as corona treatment, plasma treatment, and primer treatment as needed. When the laminate of the present invention has two or more substrates, each of the two or more substrates may be of the same type or different types.

[0117] The cured layer described above is a layer formed by curing the moisture-curing polyurethane hot melt resin composition of the present invention. Details of the moisture-curing polyurethane hot melt resin composition used in the formation of the cured layer, and preferred properties of the cured layer, are as described in section "I. Moisture-curing polyurethane hot melt resin composition" above.

[0118] Methods for forming the aforementioned cured layer include, for example, melting the moisture-curing polyurethane hot melt resin composition of the present invention at 50°C to 130°C, applying it to a substrate, and then allowing it to moisture-cur. Methods for applying the heated and molten moisture-curing polyurethane hot melt resin composition include, for example, using a roller coater, spray coater, T-die coater, blade coater, comma coater, etc.

[0119] As a method for manufacturing the laminate of the present invention, the following method can be cited: applying the moisture-curing polyurethane hot melt resin composition of the present invention to a substrate, further bonding another substrate to the coating of the resin composition, and aging for 0.5 days to 3 days under conditions such as a temperature of 20°C to 80°C and a relative humidity of 50% to 90%. Through the above aging, the coating of the resin composition becomes a cured layer, and a laminate formed by bonding the two substrates through the cured layer can be obtained, and the above-mentioned final adhesive strength can be obtained.

[0120] IV. Electronic Equipment

[0121] The electronic device of the present invention is obtained by bonding two components together via a cured layer of the moisture-curing polyurethane hot melt resin composition described in the above-mentioned item "I. Moisture-curing polyurethane hot melt resin composition".

[0122] Details regarding the moisture-curing polyurethane hot melt resin composition constituting the cured layer in the electronic device of the present invention, and the method for obtaining the aforementioned cured layer, are the same as those described in sections "I. Moisture-curing polyurethane hot melt resin composition" to "III. Laminate" above, and therefore are omitted here.

[0123] Furthermore, the components in the electronic device of the present invention are not particularly limited, and examples include housing, protective plate of information display section, image display module, display panel component, semiconductor element, light-emitting element, electronic substrate, power supply (battery), etc.

[0124] This invention is not limited to the embodiments described above. The embodiments described above are examples, and any method having a substantially the same structure and achieving the same effect as the technical concept described in the scope of this invention is included in the technical scope of this invention.

[0125] Example

[0126] The present invention will be specifically described below with examples and comparative examples.

[0127] [Examples 1-7, Comparative Examples 1-4]

[0128] Each polyol raw material shown in Table 1 was added to a four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet, and a reflux condenser in the amounts (parts by mass) recorded in the table. The mixture was heated under reduced pressure at 90°C to dehydrate it until the water content was below 0.05% by mass. Then, the temperature inside the reaction vessel was cooled to 60°C, and diphenylmethane diisocyanate (hereinafter referred to as "MDI") was added in the amounts (parts by mass) shown in Table 1. The temperature was raised to 110°C, and the reaction was carried out for about 3 hours until the isocyanate group content was constant, thereby obtaining urethane prepolymers (i-1) to (i-11) with isocyanate groups, and moisture-curing polyurethane hot melt resin compositions (1) to (11) were prepared.

[0129] The abbreviations in Table 1 represent the following materials.

[0130] PO(1): Polypropylene glycol, number average molecular weight: 1000, average number of functional groups: 2

[0131] PO(2): Polyoxyethylene polyoxypropylene glycol, number average molecular weight: 4000, EO / PO molar ratio = 10 / 90, average number of functional groups: 2

[0132] Ac(1): A polyacrylic acid polyol obtained by reacting methyl methacrylate, n-butyl methacrylate and 2-hydroxyethyl methacrylate, with a number average molecular weight of 20,000 and a glass transition temperature of 70℃.

[0133] PC(1): An amorphous polycarbonate polyol using 1,4-butanediol and 1,6-hexanediol as diol raw materials, with a number average molecular weight of 2000.

[0134] PC(2): A crystalline polycarbonate polyol using 1,6-hexanediol as the diol raw material, with a number average molecular weight of 2000.

[0135] PEs(1): Amorphous polyester polyols obtained by reacting neopentyl glycol and adipic acid, with a number average molecular weight of 2000.

[0136] PEs(2): Amorphous polyester polyols obtained by reacting 2-methyl-1,3-propanediol and adipic acid, with a number average molecular weight of 2000.

[0137] PEs(3): Crystalline polyester polyols obtained by reacting 1,4-butanediol and adipic acid, with a number average molecular weight of 1000.

[0138] PEs(4): Crystalline polyester polyols obtained by reacting 1,4-butanediol and adipic acid, with a number average molecular weight of 2000.

[0139] PEs(5): Crystalline polyester polyols obtained by reacting 1,6-hexanediol and adipic acid, with a number average molecular weight of 2000.

[0140] PEs(6): Crystalline polyester polyols obtained by reacting 1,6-hexanediol and dodecanoic acid, with a number average molecular weight of 3500.

[0141] [Methods for determining number-average molecular weight]

[0142] The number-average molecular weights of the polyols used in the preparation of the urethane prepolymers in the Examples and Comparative Examples are expressed as values ​​determined by gel permeation chromatography (GPC) under the following conditions.

[0143] Measurement apparatus: High-speed GPC apparatus (Tosoh Corporation "HLC-8220 GPC")

[0144] Column: Used to connect the following columns manufactured by Tosoh Corporation in series.

[0145] "TSKgel G 5000" (7.8 mm ID×30 cm) × 1 piece

[0146] "TSKgel G 4000" (7.8 mm ID×30 cm) × 1 piece

[0147] "TSKgel G 3000" (7.8 mm ID×30 cm) × 1 piece

[0148] "TSKgel G 2000" (7.8 mm ID×30 cm) × 1 piece

[0149] Detector: RI (Differential Refractometer)

[0150] Column temperature: 40℃

[0151] Eluent: Tetrahydrofuran (THF)

[0152] Flow rate: 1.0 mL / min

[0153] Injection volume: 100 μL (0.4% by mass tetrahydrofuran solution containing the sample)

[0154] Standard test specimen: A calibration curve was prepared using the following standard polystyrene.

[0155] (Standard polystyrene)

[0156] TSKgel Standard Polystyrene A-500 manufactured by Tosoh Corporation

[0157] TSKgel Standard Polystyrene A-1000 manufactured by Tosoh Corporation

[0158] TSKgel Standard Polystyrene A-2500 manufactured by Tosoh Corporation

[0159] TSKgel Standard Polystyrene A-5000 manufactured by Tosoh Corporation

[0160] TSKgel Standard Polystyrene F-1 manufactured by Tosoh Corporation

[0161] TSKgel Standard Polystyrene F-2 manufactured by Tosoh Corporation

[0162] TSKgel Standard Polystyrene F-4 manufactured by Tosoh Corporation

[0163] TSKgel Standard Polystyrene F-10 manufactured by Tosoh Corporation

[0164] TSKgel Standard Polystyrene F-20 manufactured by Tosoh Corporation

[0165] TSKgel Standard Polystyrene F-40 manufactured by Tosoh Corporation

[0166] TSKgel Standard Polystyrene F-80 manufactured by Tosoh Corporation

[0167] TSKgel Standard Polystyrene F-128 manufactured by Tosoh Corporation

[0168] TSKgel Standard Polystyrene F-288 manufactured by Tosoh Corporation

[0169] TSKgel Standard Polystyrene F-550 manufactured by Tosoh Corporation

[0170] [Table 1]

[0171]

[0172] <Evaluation>

[0173] The moisture-curing polyurethane hot melt resin compositions of the Examples and Comparative Examples were evaluated as follows. The evaluation results are shown in Tables 2-3.

[0174] [1. Normal strength and thermal strength]

[0175] A moisture-curing polyurethane hot-melt resin composition was heated to 110°C for 30 minutes to melt it. Using a dispenser needle (Musashi Engineering Co., Ltd. "SHOT MASTER 300DS") with an inner diameter of 0.35 mm and preheated at 110°C, the mixture was applied in a straight line with a length of 25 mm onto a polycarbonate sheet (PC sheet) (25 mm × 100 mm) at a processing speed of 50 mm / s. Sixty seconds after application, another PC sheet (25 mm × 100 mm) was placed from above, holding a 0.15 mm spacer, and the two sheets were bonded together with an overlap of 1 mm in the moisture-curing polyurethane hot-melt resin composition. The mixture was then placed in a constant temperature and humidity chamber at 23°C and 50% humidity for 72 hours to obtain the laminate used in the determination of its normal strength and thermal strength.

[0176] For the laminate obtained above, the maximum tensile strength was measured at 23°C using a benchtop precision universal testing machine (Autograph AGS-5kNX, Shimadzu Corporation) at a tensile speed of 10 mm / min. The measured maximum tensile strength was divided by the area of ​​the moisture-curing polyurethane hot melt resin composition, and the resulting value was taken as the normal strength [MPa]. Furthermore, for the laminate obtained above, the same measurement was performed at 60°C. The measured maximum tensile strength was divided by the area of ​​the moisture-curing polyurethane hot melt resin composition, and the resulting value was taken as the thermal strength [MPa].

[0177] [2. Drop impact resistance]

[0178] The moisture-curing type polyurethane hot-melt resin composition was heated and melted at 110°C for 30 minutes. Using a dispenser needle (dispenser "SHOT MASTER 300DS" manufactured by Musashi Engineering Co., Ltd.) with an inner diameter of 0.35 mm that had been heated at 110°C, it was coated in a 1-inch circle on a PC board (50 mm × 90 mm) having a 10-mm diameter hole in the central part at a processing speed of 50 mm / second. Sixty seconds after coating, while holding a 0.15-mm spacer, another PC board (50 mm × 50 mm) was laminated from above, and then it was placed in a thermo-hygrostat at a temperature of 23°C and a humidity of 50% RH for 72 hours, thereby obtaining a laminate used in the measurement of the drop impact resistance.

[0179] Using a DuPont type drop impact tester, three impacts were given to the above-obtained laminate from a PC board having a 10-mm diameter hole in the central part through an impact core at a load of 200 g and a height of 5 cm. If no peeling of the PC board occurred, visual observation was made for peeling under the condition of giving an impact at +5 cm, and the height [cm] at which peeling of the PC board occurred was measured.

[0180] [3. Thixotropy (thixotropy index (TI))]

[0181] After setting the cone-plate viscometer CV-1 (manufactured by Toa Kogyo Co., Ltd.) at 110°C and heating it, the moisture-curing type polyurethane hot-melt resin composition that had been heated and melted at 110°C was sandwiched between the cone and the plate, and the melt viscosity (η5) at a rotor speed of 5 rpm and the melt viscosity (η 50 ) at 50 rpm were measured, and the thixotropy index (TI) was calculated according to the following formula.

[0182] Thixotropy index (TI) = (melt viscosity η5 at 5 rpm) / (melt viscosity η 50 )

[0183] [4. Storage modulus E’(25) and E’(60), and tanδ peak temperature]

[0184] After molding a moisture-curing polyurethane hot melt resin composition that had been heated and melted at 110°C to a thickness of 100 μm using a roller coater, the molded product was placed in a constant temperature and humidity bath at 23°C and 50% RH for 72 hours, thereby obtaining a molded product with a thickness of 100 μm. For the molded product of this moisture-curing polyurethane hot melt resin composition, the storage modulus and loss tangent were measured using a viscoelasticity measuring device (DMS 6100 manufactured by SIINano Technology) under the following conditions. The storage modulus at 25°C is taken as E'(25) [MPa], and the storage modulus at 60°C is taken as E'(60) [MPa]. In addition, the temperature at which the loss tangent tanδ peaks below 25°C is taken as the tanδ peak temperature [°C].

[0185] (condition)

[0186] Temperature range: -100~200℃

[0187] Heating rate: 5℃ / minute

[0188] Frequency: 1 Hz

[0189] Mode: Stretch mode

[0190] [Table 2]

[0191]

[0192] [Table 3]

[0193]

Claims

1. A moisture-curing polyurethane hot melt resin composition comprising a urethane prepolymer i having isocyanate groups, wherein the urethane prepolymer i is made from polyol A and polyisocyanate B. The ratio of the storage modulus E'(25) at 25°C to the storage modulus E'(60) at 60°C, i.e., E'(25) / E'(60), of the cured product of the moisture-curing polyurethane hot melt resin composition is in the range of 1.0 to 10.

0.

2. The moisture-curing polyurethane hot melt resin composition according to claim 1, wherein, The cured product of the moisture-curing polyurethane hot melt resin composition has a storage modulus E'(60) at 60°C in the range of 10 MPa to 50 MPa. The cured product of the moisture-curing polyurethane hot melt resin composition has a storage modulus E'(25) at 25°C in the range of 30 MPa to 150 MPa.

3. The moisture-curing polyurethane hot melt resin composition according to claim 1, wherein, The peak temperature of the loss tangent of the cured product of the moisture-curing polyurethane hot melt resin composition is below -15°C.

4. The moisture-curing polyurethane hot melt resin composition according to claim 1, wherein the thixotropic index (TI) is in the range of 1.11 to 1.

80.

5. The moisture-curing polyurethane hot melt resin composition according to claim 1, wherein, The polyol A contains at least polyether polyol a1 and polyacrylic acid polyol a2.

6. The moisture-curing polyurethane hot melt resin composition according to claim 5, wherein, The polyether polyol a1 comprises a high molecular weight polyether polyol. The content of the high molecular weight polyether polyol is 10 to 50 parts by mass in 100 parts by mass of the raw material of the urethane prepolymer i.

7. The moisture-curing polyurethane hot melt resin composition according to claim 5, wherein, The content of the polyacrylic acid polyol a2 is 3 to 20 parts by mass in 100 parts by mass of the raw material of the urethane prepolymer i.

8. The moisture-curing polyurethane hot melt resin composition according to claim 1, wherein, The polyol A further comprises polyether polyol a1 and polyacrylic acid polyol a2, and at least one selected from polyester polyol a3 and polycarbonate polyol a4.

9. The moisture-curing polyurethane hot melt resin composition according to claim 1, wherein, The content of the polyisocyanate B is 10 to 40 parts by mass in 100 parts by mass of the raw material of the urethane prepolymer i.

10. An adhesive comprising the moisture-curing polyurethane hot melt resin composition according to any one of claims 1 to 9.

11. A laminate having at least a substrate and a cured layer of the moisture-curing polyurethane hot melt resin composition according to any one of claims 1 to 9.

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