JP2020097653A - Moisture-curable polyurethane hot-melt resin composition, adhesive, and article - Google Patents

Abstract

To provide a moisture-curable polyurethane hot-melt resin composition excellent in initial adhesiveness and hydrolysis resistance.SOLUTION: The present invention provides the moisture-curable polyurethane hot-melt resin composition containing a urethane prepolymer having isocyanate groups, which is a reaction product of a polyol (a) and a polyisocyanate (b). The polyol (a) contains an alicyclic polycarbonate polyol (a-1), a crystalline polyester polyol (a-2), and a polyether polyol (a-3). The polyisocyanate (b) contains a diisocyanate (b-1), a polymethylene polyphenyl polyisocyanate (b-2), and an isocyanurate compound (b-3).SELECTED DRAWING: None

Description

The present invention relates to a moisture-curable polyurethane hot melt resin composition and an adhesive.

BACKGROUND ART A decorative plate in which a decorative sheet is attached to a plate-shaped base material is widely used as a building interior material such as a floor material, a door, a fabrication member, and a top plate. Up to now, a urethane adhesive, an epoxy adhesive, a modified silicone resin adhesive, an acrylic adhesive, etc. have been used to bond the base material and the decorative sheet. Among these, in recent years, the use of moisture-curable polyurethane hot melt adhesives that exhibit excellent final adhesive strength by moisture curing is increasing.

As the moisture-curable polyurethane hot melt adhesive used for the decorative board, for example, an isocyanate-terminated urethane prepolymer, a specific amount of an epoxy group-containing silane coupling agent and a (meth) acryloyl group-containing silane coupling agent. A moisture-curable polyurethane hot-melt adhesive agent containing it is disclosed (for example, refer to Patent Document 1).

However, it has been pointed out that the adhesive sheet has insufficient initial adhesive strength (initial adhesiveness) and insufficient hydrolysis resistance, so that the decorative sheet may come off over time.

JP, 2011-225635, A

The problem to be solved by the present invention is to provide a moisture-curable polyurethane hot melt resin composition which is excellent in initial adhesion and hydrolysis resistance.

The present invention is a moisture-curable polyurethane hot melt resin composition containing a urethane prepolymer having an isocyanate group, which is a reaction product of a polyol (a) and a polyisocyanate (b), wherein the polyol (a) is a fat. It contains a cyclic polycarbonate polyol (a-1), a crystalline polyester polyol (a-2), and a polyether polyol (a-3), and the polyisocyanate (b) is a diisocyanate (b-1) or a polyisocyanate (b-1). The present invention provides a moisture-curable polyurethane hot melt resin composition containing methylene polyphenyl polyisocyanate (b-2) and isocyanurate compound (b-3).

Further, the present invention provides an adhesive containing the moisture-curable hot melt resin composition, and an article characterized by being bonded with the adhesive.

The moisture-curable polyurethane hot melt resin composition of the present invention has excellent initial adhesion and hydrolysis resistance.

Therefore, the moisture-curable polyurethane hot melt resin composition of the present invention can be suitably used as an adhesive for laminating decorative boards. The obtained decorative boards are used as flooring materials; lower foot doors, closet doors, kitchen doors, etc.; frame materials, picture frames, skirting boards, etc.; counter tables, furniture top boards, etc. It can be preferably used.

The moisture-curable polyurethane hot melt resin composition of the present invention contains a urethane prepolymer having an isocyanate group, which is a reaction product of a specific polyol (a) and a specific polyisocyanate (b).

The polyol (a) contains an alicyclic polycarbonate polyol (a-1), a crystalline polyester polyol (a-2), and a polyether polyol (a-3) as essential components.

The alicyclic polycarbonate polyol (a-1) is an essential component for obtaining excellent initial adhesion and hydrolysis resistance. Due to the packing effect of the alicyclic structure of the polycarbonate polyol (a-2), good cohesive force is obtained and excellent initial adhesiveness is exhibited.

As the alicyclic polycarbonate polyol (a-1), for example, a reaction product of a carbonic acid ester and/or phosgene and a polyol compound containing an alicyclic polyol having a molecular weight of 50 to 400 can be used. The molecular weight of the alicyclic polyol is a value calculated from the chemical structural formula.

As the carbonic acid ester, for example, methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate, diphenyl carbonate or the like can be used. These compounds may be used alone or in combination of two or more kinds.

Examples of the alicyclic polyol include 1,2-cyclobutanediol, 1,3-cyclopentanediol, 1,4-cyclohexanediol, cycloheptanediol, cyclooctanediol, 1,4-cyclohexanedimethanol and hydroxypropyl. Cyclohexanol, tricyclo[5,2,1,0 ^2,6 ]decane-dimethanol, bicyclo[4.3,0]-nonanediol, dicyclohexanediol, tricyclo[5,3,1,1]dodecanediol, Bicyclo[4,3,0]nonanedimethanol, tricyclo[5,3,1,1]dodecane-diethanol, hydroxypropyltricyclo[5,3,1,1]dodecanol, spiro[3,4]octanediol, Butyl cyclohexane diol, 1,1′-bicyclohexylidene diol, cyclohexane triol, hydrogenated bisphenol A, 1,3-adamantane diol and the like can be used. These compounds may be used alone or in combination of two or more kinds. Among these, it is preferable to use 1,4-cyclohexanedimethanol from the viewpoints of further excellent low viscosity, initial adhesion and hydrolysis resistance.

The amount of the alicyclic polyol used is preferably 20% by mass or more, and more preferably 30% by mass or more in the polyol compound from the viewpoint of further excellent initial adhesion and hydrolysis resistance.

Examples of the polyol compound that can be used other than the alicyclic polyol include, for example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, and tripropylene glycol. Propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 1,6-hexane Diol, 2,5-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol , 2-methyl-1,3-propanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3- Hexanediol, 2-methyl-1,8-octanediol, glycerin, trimethylolpropane, ditrimethylolpropane, tritrimethylolpropane, pentaerythritol and the like can be used. Among these, it is preferable to use 1,6-hexanediol from the viewpoint of obtaining further excellent low viscosity, initial adhesiveness, flexibility and hydrolysis resistance.

The number average molecular weight of the alicyclic polycarbonate polyol (a-1) is preferably in the range of 500 to 5,000 from the viewpoint of obtaining further excellent initial adhesion and hydrolysis resistance. The range of -3,000 is more preferable, and the range of 800-2,000 is more preferable. The number average molecular weight of the alicyclic polycarbonate polyol (a-1) is a value measured by a gel permeation chromatography (GPC) method.

The amount of the alicyclic polycarbonate polyol (a-1) used is the total mass of the polyol (a) and the polyisocyanate (b) from the viewpoint that further excellent initial adhesion and hydrolysis resistance can be obtained. The range is preferably 1 to 40% by mass, more preferably 3 to 30% by mass, and further preferably 5 to 20% by mass.

The crystalline polyester polyol (a-2) is an essential component for obtaining excellent initial adhesiveness and final adhesiveness. As the crystalline polyester polyol (a-2), for example, a reaction product of a compound having a hydroxyl group and a polybasic acid can be used. In the present invention, “crystalline” means that a peak of crystallization heat or a heat of fusion can be confirmed in DSC (differential scanning calorimeter) measurement in accordance with JIS K7121:2012, and is “amorphous”. Indicates that the peak cannot be confirmed.

Examples of the compound having a hydroxyl group include ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, trimethylolpropane, trimethylolethane, and glycerin. You can These compounds may be used alone or in combination of two or more kinds. Among these, at least one selected from the group consisting of butanediol, hexanediol, octanediol, and decanediol is used from the viewpoint of enhancing crystallinity and obtaining more excellent initial adhesion and final adhesion. Is preferred, and 1,6-hexanediol is more preferred.

As the polybasic acid, for example, oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedicarboxylic acid and the like can be used. These polybasic acids may be used alone or in combination of two or more kinds. Among these, it is preferable to use at least one selected from the group consisting of adipic acid, sebacic acid, and dodecanedicarboxylic acid from the viewpoint of increasing crystallinity and obtaining more excellent initial adhesiveness and final adhesiveness. preferable.

The number average molecular weight of the crystalline polyester polyol (a-2) is in the range of 500 to 10,000 from the viewpoint of obtaining more excellent low viscosity, initial adhesiveness, and final adhesiveness. Is preferable, the range of 1,000 to 8,000 is more preferable, and the range of 1,500 to 5,000 is further preferable. The number average molecular weight of the crystalline polyester polyol (a-2) is a value measured by a gel permeation chromatography (GPC) method.

The amount of the crystalline polyester polyol (a-2) used is the total mass of the polyol (a) and the polyisocyanate (b) from the viewpoint that more excellent initial adhesiveness and final adhesiveness are obtained. The range is preferably 5 to 50% by mass, more preferably 7 to 45% by mass, and further preferably 10 to 40% by mass.

The polyether polyol (a-3) is an essential component for ensuring low viscosity, flexibility and coatability. Examples of the polyether polyol (a-3) include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyoxyethylene polyoxypropylene glycol, polyoxyethylene polyoxytetramethylene glycol, polyoxypropylene polyoxytetramethylene glycol. , Polyoxypropylene triol and the like can be used. These polyether polyols may be used alone or in combination of two or more kinds.

Among these, it is preferable to use polypropylene glycol and/or polyoxyethylene polyoxypropylene glycol from the viewpoint that further excellent hydrolysis resistance, low viscosity, flexibility, and coatability can be obtained. It is preferable to use polypropylene glycol and polyoxyethylene polyoxypropylene glycol together.

When the polypropylene glycol (PO) and polyoxyethylene polyoxypropylene glycol (EOPO) are used in combination, the mass ratio [PO/EOPO] is further excellent in hydrolysis resistance, low viscosity, flexibility, and From the viewpoint of obtaining coatability, the range of 30/70 to 90/10 is preferable, the range of 40/60 to 80/20 is more preferable, and the range of 50/50 to 70/30 is further preferable. ..

The number average molecular weight of the polyether polyol (a-3) is in the range of 500 to 100,000 from the viewpoint that further excellent hydrolysis resistance, low viscosity, flexibility and coatability can be obtained. Is more preferable, the range of 550-10,000 is more preferable, and the range of 600-6,000 is still more preferable. The number average molecular weight of the polyether polyol (a-3) is a value measured by a gel permeation chromatography (GPC) method.

As the amount of the polyether polyol (a-3) to be used, the polyol (a) and the poly (polyether) can be used because the hydrolysis resistance, the low viscosity, the flexibility, and the coating property are more excellent. The total amount of the isocyanate (b) is preferably in the range of 5 to 40% by mass, more preferably 10 to 30% by mass.

The polyol (a) contains the alicyclic polycarbonate polyol (a-1), the crystalline polyester polyol (a-2), and the polyether polyol (a-3) as essential components, but if necessary. Therefore, other polyols may be used in combination. The total amount of the components (a-1) to (a-3) used in the polyol (a) is preferably 40% by mass or more, more preferably 50% by mass or more.

Examples of the other polyols include a polycarbonate polyol (a-4) having no alicyclic structure, a polyester polyol other than the crystalline polyester polyol (a-2), a polyacrylic polyol, a polybutadiene polyol, a hydrogenated polybutadiene polyol, and the like. Can be used. These polyols may be used alone or in combination of two or more. Among these, it is more preferable to use the polycarbonate polyol (a-4) which does not have an alicyclic structure, from the viewpoint that even more excellent initial adhesion and hydrolysis resistance can be obtained.

As the polycarbonate polyol (a-4), for example, a reaction product of the same carbonic acid ester and/or phosgene as the raw material of the alicyclic polycarbonate polyol (a-1) and a polyol compound other than the alicyclic polyol. Can be used.

The number average molecular weight of the polycarbonate polyol (a-4) is preferably in the range of 500 to 5,000, and more preferably 700 to 3, from the viewpoint of obtaining more excellent initial adhesion and hydrolysis resistance. The range of 000 is more preferable. The number average molecular weight of the polycarbonate polyol (a-4) is a value measured by a gel permeation chromatography (GPC) method.

When the polycarbonate polyol (a-4) is used, the amount used is 0.1 in the total mass of the polyol (a) and the polyisocyanate (b) from the viewpoint that more excellent substrate adhesion can be obtained. The range is preferably from 20 to 20% by mass, more preferably from 1 to 15% by mass.

Moreover, when using the said polycarbonate polyol (a-4), the mass ratio [(a-1)/(a-4) of the said alicyclic polycarbonate polyol (a-1) and the said polycarbonate polyol (a-4). )] is preferably in the range of 30/70 to 90/10, and 40/60 to 80/20, from the viewpoint of obtaining further excellent substrate adhesion, initial adhesion and hydrolysis resistance. Is more preferable, and the range of 50/50 to 70/30 is further preferable.

As the polyisocyanate (b), a diisocyanate (b-1), a polymethylene polyphenyl polyisocyanate (b-2), and a polyisocyanate (b-1) in order to form a crosslinked structure and obtain excellent initial adhesion and hydrolysis resistance, It is essential to contain the isocyanurate compound (b-3).

Examples of the diisocyanate (b-1) include aromatic diisocyanates such as diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate isocyanate, xylylene diisocyanate, phenylene diisocyanate, tolylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, Diisocyanates such as aliphatic or alicyclic diisocyanates such as dicyclohexylmethane diisocyanate and tetramethylxylylene diisocyanate can be used. These polyisocyanates may be used alone or in combination of two or more kinds. Among these, aromatic polyisocyanates are preferable, and diphenylmethane diisocyanate is more preferable, because more excellent reactivity and adhesiveness are obtained.

The amount of the diisocyanate (b-1) to be used is 1 to 20 in the total mass of the polyol (a) and the polyisocyanate (b) from the viewpoint that further excellent initial adhesion and hydrolysis resistance can be obtained. It is preferably in the range of mass% and more preferably in the range of 7 to 17 mass %.

（式（２）中、ｎは１以上の整数である。） The polymethylene polyphenyl polyisocyanate (b-2) is specifically one represented by the following formula (2), preferably n in the formula (2) is an integer of 1 to 5. is there.

(In the formula (2), n is an integer of 1 or more.)

The amount of the polymethylene polyphenyl polyisocyanate (b-2) to be used is 0. 0 based on the total mass of the polyol (a) and the polyisocyanate (b) from the viewpoint of further excellent hydrolysis resistance. It is preferably in the range of 5 to 15% by mass, more preferably in the range of 2 to 10% by mass.

As the isocyanurate compound (b-3), for example, an isocyanurate body of the diisocyanate (b-1) can be used. As the raw material diisocyanate, an aliphatic diisocyanate is preferably used, and hexamethylene diisocyanate is more preferable, from the viewpoint that more excellent initial adhesive strength and hydrolysis resistance can be obtained.

The amount of the isocyanurate compound (b-4) to be used is 0 in the total mass of the polyol (a) and the polyisocyanate (b) from the viewpoint that further excellent initial adhesion and hydrolysis resistance can be obtained. It is preferably in the range of 1 to 15% by mass, more preferably in the range of 1 to 10% by mass.

The polyisocyanate (b) contains the diisocyanate (b-1), the polymethylene polyphenylmethane diisocyanate (b-2), and the isocyanurate compound (b-3) as essential components, but if necessary, , Other polyisocyanates may be contained. The total amount of the components (b-1) to (b-3) used in the polyiso left fly nate (b) is preferably 80% by mass or more, more preferably 90% by mass or more.

As the other polyisocyanate, for example, an adduct body of the diisocyanate (b-1); a burette body or the like can be used. These polyisocyanates may be used alone or in combination of two or more kinds.

The urethane prepolymer is obtained by reacting the polyol (a) with the polyisocyanate (b), and reacts with water present in the air or a base material to which the urethane prepolymer is applied. It has an isocyanate group capable of forming a crosslinked structure.

As the method for producing the urethane prepolymer, for example, a reaction vessel containing the polyisocyanate (b) is heated after dropping the mixture of the polyol (a), and the isocyanate group contained in the polyisocyanate (b) is It can be produced by reacting the polyol (a) with an excessive amount of hydroxyl groups.

When producing the urethane prepolymer, the molar ratio (NCO/OH) of the hydroxyl group of the polyol (a) and the isocyanate group of the polyisocyanate (b) reduces unreacted polyisocyanate, and is more excellent. The range of 1.5 to 7 is preferable, and the range of 1.8 to 3 is more preferable, from the viewpoint that adhesiveness is obtained.

The isocyanate group content (hereinafter abbreviated as "NCO%") of the urethane prepolymer obtained by the above method is in the range of 1 to 10% by mass from the viewpoint of further excellent adhesiveness. It is preferably present, more preferably in the range of 2 to 5% by mass, and further preferably in the range of 2.5 to 4% by mass. The NCO% of the urethane prepolymer is a value measured by a potentiometric titration method based on JISK1603-1:2007.

The moisture-curable polyurethane hot melt resin composition of the present invention contains the urethane prepolymer, but may contain other additives as required.

Examples of the other additives include curing catalysts, antioxidants, tackifiers, plasticizers, light stabilizers, fillers, dyes, pigments, defoamers, optical brighteners, silane coupling agents, waxes. A thermoplastic resin or the like can be used. These additives may be used alone or in combination of two or more.

Next, the article will be described.

The article is obtained by bonding at least two articles with an adhesive containing the moisture-curable polyurethane hot melt resin composition.

Examples of the article to be laminated include wood base materials such as plate-like wood, laminated wood, plywood, MDF (medium density fiberboard), particle board; inorganic base materials such as hard cement calcium silicate board; resins. Sheets; glass; rubber; plastic molded products; decorative paper, non-woven fabrics, woven fabrics, veneers, tatami mats, etc. can be used.

The adhesive layer can be appropriately determined as long as sufficient adhesiveness can be obtained, and for example, the range of 0.03 to 0.15 mm can be mentioned.

As described above, the moisture-curable polyurethane hot melt resin composition of the present invention has excellent initial adhesion and hydrolysis resistance.

Therefore, the moisture-curable polyurethane hot melt resin composition of the present invention can be suitably used as an adhesive for laminating decorative boards. The obtained decorative boards are used as floor materials; lower foot doors, closet doors, kitchen doors, etc.; frame materials, picture frames, skirting boards, etc.; counter tables, furniture top boards, etc. It can be used preferably.

Hereinafter, the present invention will be described in more detail with reference to examples.

[Example 1]
In a four-necked flask equipped with a stirrer, a thermometer, an inert gas inlet and a reflux condenser, an alicyclic polycarbonate polyol (using 1,4-cyclohexanedimethanol as a raw material, a number average molecular weight of 1,000, Hereinafter, abbreviated as “alicyclic PC”. 15 parts by mass, crystalline polyester polyol (reaction product of 1,6-hexanediol and 1,12-dodecanedicarboxylic acid, number average molecular weight: 3,500, hereinafter “crystallinity” PEs1") 35 parts by mass, polypropylene glycol (number average molecular weight; 2,000, hereinafter abbreviated as "PPG") 13 parts by mass, polyoxyethylene polyoxypropylene glycol (number average molecular weight; 4000, or less) Abbreviated as "EOPO") 7 parts by mass, liquid polyester polyol (diethylene glycol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol and adipic acid reaction product, number average molecular weight; 2, 000, hereinafter abbreviated as “other PEs.”) 5 parts by mass were charged and dehydrated by heating at 90° C. under reduced pressure until the water content became 0.05% by mass or less.
Then, after cooling the temperature in the reaction vessel to 60° C., 13 parts by mass of 4,4′-diphenylmethane diisocyanate (hereinafter abbreviated as “MDI”) and polymethylene polyphenyl polyisocyanate (“Millionate MR- manufactured by Tosoh Corporation”) were used. 200", hereinafter abbreviated as "cMDI") 7 parts by mass, 5 parts by mass of hexamethylene diisocyanate isocyanurate (hereinafter abbreviated as "HDI-N"), and heated to 110°C. A urethane prepolymer having an isocyanate group was obtained by reacting for about 3 hours until the isocyanate group content became constant.

[Examples 2 to 5, Comparative Examples 1 to 3]
A urethane prepolymer was obtained in the same manner as in Example 1 except that the amounts of various polyols used were changed as shown in Tables 1 and 2.

[Measurement method of number average molecular weight]
The number average molecular weight of the polyols used in Examples and Comparative Examples is a value measured by the gel permeation chromatography (GPC) method under the following conditions.

Measuring device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were connected in series and used.
"TSKgel G5000" (7.8 mm ID x 30 cm) x 1 "TSK gel G4000" (7.8 mm ID x 30 cm) x 1 "TSK gel G3000" (7.8 mm ID x 30 cm) x 1 This "TSKgel G2000" (7.8 mm ID x 30 cm) x 1 Detector: RI (differential refractometer)
Column temperature: 40°C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL/min Injection volume: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4% by mass)
Standard sample: A calibration curve was prepared using the following standard polystyrene.

(Standard polystyrene)
Tosoh Corporation "TSKgel Standard Polystyrene A-500"
Tosoh Corporation "TSK gel standard polystyrene A-1000"
Tosoh Corporation "TSK gel standard polystyrene A-2500"
Tosoh Corporation "TSK gel standard polystyrene A-5000"
"TSK gel standard polystyrene F-1" manufactured by Tosoh Corporation
"TSK gel standard polystyrene F-2" manufactured by Tosoh Corporation
"TSK gel standard polystyrene F-4" manufactured by Tosoh Corporation
Tosoh Corporation "TSKgel Standard Polystyrene F-10"
Tosoh Corporation "TSK gel standard polystyrene F-20"
Tosoh Corporation "TSK gel standard polystyrene F-40"
Tosoh Corporation "TSK gel standard polystyrene F-80"
Tosoh Corporation "TSK gel standard polystyrene F-128"
Tosoh Corporation "TSK gel standard polystyrene F-288"
Tosoh Corporation "TSK gel standard polystyrene F-550"

[Evaluation method of initial adhesion]
The moisture-curable polyurethane hot melt resin compositions obtained in Examples and Comparative Examples were heated and melted at 120° C., coated on a polyethylene terephthalate (PET) sheet so as to have a thickness of 50 μm, and then coated on the coated surface. An MDF (medium density fiberboard) was placed and laminated. Three minutes after the bonding, in a 35° C. atmosphere, a load of 75 g was applied in a 90° direction with respect to a width of 25 mm, and after 15 minutes, the peel length of the PET sheet was measured and evaluated as follows.
"T": The peel length is less than 5 mm.
"F": The peeling length is 5 mm or more.

[Hydrolysis resistance evaluation method]
The moisture-curable polyurethane hot melt resin compositions obtained in Examples and Comparative Examples were heated and melted at 120° C., coated on a polyethylene terephthalate (PET) sheet so as to have a thickness of 50 μm, and then coated on the coated surface. An MDF (medium density fiberboard) was placed and laminated. This was left under conditions of 23° C. and 50% humidity for 5 days. After that, in an atmosphere of 85°C and a humidity of 85%. A load of 70° C. was applied to the 25 mm width in the 90° direction, and the number of days until the PET sheet was peeled by 40 mm was measured and evaluated as follows.
"T": 35 days or more "F": less than 35 days

The abbreviations in Tables 1 and 2 are as follows.
"Crystalline PEs2": reaction product of 1,6-hexanediol and adipic acid, number average molecular weight; 4,500
"PC": Polycarbonate polyol prepared from 1,5-pentanediol and 1,6-hexanediol as raw materials, number average molecular weight: 2,000

It has been found that the moisture-curable polyurethane hot melt resin composition of the present invention has excellent initial adhesion and hydrolysis resistance.

On the other hand, in Comparative Example 1, the crystalline polyester polyol (a-2) was not used, but the initial adhesiveness was poor.

Comparative Example 2 was an embodiment in which the alicyclic polycarbonate polyol (a-1) was not used, but the initial adhesiveness was poor.

Comparative Example 3 is a mode in which the polymethylene polyphenyl polyisocyanate (b-2) and the isocyanurate compound (b-3) are not used, but the initial adhesion and hydrolysis resistance were poor.

Claims (5)

A moisture-curable polyurethane hot melt resin composition containing a urethane prepolymer having an isocyanate group, which is a reaction product of a polyol (a) and a polyisocyanate (b),
The polyol (a) is
Contains alicyclic polycarbonate polyol (a-1), crystalline polyester polyol (a-2), and polyether polyol (a-3),
The polyisocyanate (b) is
A moisture-curable polyurethane hot melt resin composition comprising a diisocyanate (b-1), a polymethylene polyphenyl polyisocyanate (b-2), and an isocyanurate compound (b-3). The moisture-curable polyurethane hot melt resin composition according to claim 1, wherein the polyether polyol (a-3) contains polypropylene glycol and polyoxyethylene polyoxypropylene glycol. The moisture-curable polyurethane hot melt resin composition according to claim 1 or 2, wherein the polyol (a) further contains a polycarbonate polyol (a-4) having no alicyclic structure. An adhesive comprising the moisture-curable polyurethane hot melt resin composition according to any one of claims 1 to 3. An article having an adhesive part formed by the adhesive according to claim 4.