TW202112865A - Moisture-curable polyurethane hot-melt resin composition - Google Patents

Abstract

The present invention addresses the problem of providing a moisture-curable polyurethane hot-melt resin composition having excellent low-viscosity, initial adhesive strength, flexibility, coating suitability, and hydrolysis resistance. The present invention provides a moisture-curable polyurethane hot-melt resin composition characterized by containing a urethane prepolymer (i) which is made from a polyol (A) and a polyisocyanate (B) and has an isocyanate group, wherein the polyol (A) contains a polyester polyol (a1) made from adipic acid, a polyether polyol (a2), and an aromatic polyester polyol (a3), and the total used amount of the polyester polyol (a1) and the polyether polyol (a2) is larger than the used amount of the aromatic polyester polyol (a3).

Description

Moisture hardening polyurethane hot-melt resin composition

The invention relates to a moisture-curing polyurethane hot-melt resin composition.

Moisture-curing polyurethane hot-melt adhesives are solvent-free. Therefore, as environmentally compatible adhesives, various researches centered on fiber bonding and building materials lamination have been carried out, and they are also used in the industry. Is widely used.

The moisture-curing polyurethane adhesive exhibits the final adhesive strength by moisture curing of the isocyanate group of the urethane prepolymer as its main agent, but it is in various types. In the bonding of such substrates, even immediately after application of the adhesive, high initial bonding strength is required.

In order to obtain high initial adhesive strength, crystalline polyester polyols are generally used in large amounts (for example, refer to Patent Document 1). However, regarding the above method, there are accusations that the viscosity is high and coating is difficult, or the obtained hardened film is also hard, so, for example, in fiber applications and other fields requiring flexibility, the hand feel is reduced. In addition, if a large amount of polyester polyol is used, the hydrolysis resistance also becomes poor, so the current situation is that the utilization is not promoted. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2011-190309

[The problem to be solved by the invention] The problem to be solved by the present invention is to provide a moisture-curable polyurethane hot-melt resin composition with excellent low viscosity, initial adhesive strength, flexibility, coating adaptability, and hydrolysis resistance. [Means to solve the problem]

The present invention provides a moisture-curing polyurethane hot-melt resin composition, which contains a polyurethane prepolymer (i ), and the moisture-curing polyurethane hot-melt resin composition is characterized in that: the polyol (A) contains adipic acid-based polyester polyol (a1), polyether polyol Alcohol (a2) and aromatic polyester polyol (a3), the total usage amount of the polyester polyol (a1) and the polyether polyol (a2) is greater than that of the aromatic polyester polyol (a3) ) Usage. [Effects of the invention]

The moisture-curing polyurethane hot-melt resin composition of the present invention is excellent in low viscosity, initial adhesive strength, flexibility, coating suitability, and hydrolysis resistance. Therefore, the moisture-curing polyurethane hot-melt resin composition of the present invention can be particularly suitably used for fiber applications.

The moisture-curing polyurethane hot-melt resin composition of the present invention comprises a polyol (A) containing a specific polyol and a polyisocyanate (B) as raw materials, and a urethane prepolymer having an isocyanate group物(i).

The polyol (A) contains a polyester polyol (a1), a polyether polyol (a2), and an aromatic polyester polyol (a3) using adipic acid as a raw material.

The polyester polyol (a1) is an essential component in order to obtain excellent initial adhesive strength and flexibility. For example, a reaction product of a polybasic acid containing adipic acid and a compound having two or more hydroxyl groups can be used.

Examples of polybasic acids other than adipic acid include succinic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedioic acid, and dodecanedioic acid. , Eicosandioic acid, citraconic acid, itaconic acid, citraconic anhydride, itaconic anhydride and other aliphatic polybasic acids; 1,4-cyclohexanedicarboxylic acid and other alicyclic polybasic acids, etc. These polybasic acids may be used alone, or two or more of them may be used in combination. The amount of the adipic acid used in the polybasic acid is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, particularly preferably 90% by mass or more.

As the compound having two or more hydroxyl groups, for example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1 ,7-Heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-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- Propylene glycol, 3-methyl-1,5-pentanediol, 2-ethyl-2-butyl-1,3-propanediol, 2-methyl-1,8-octanediol, 2,4-diethyl Alpha-1,5-pentanediol, trimethylolethane, trimethylolpropane, pentaerythritol and other aliphatic compounds; cyclopentanediol, cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, Alicyclic compounds such as these alkylene oxide adducts and the like. These compounds may be used alone, or two or more of them may be used in combination. Among these, it is preferable to use an aliphatic compound and/or an alicyclic compound, and more preferably to use an aliphatic compound and/or an alicyclic compound, in terms of obtaining further excellent initial bonding strength and flexibility, and more preferably to use selected from ethylene glycol, 1,4 -Butanediol, diethylene glycol, neopentyl glycol, 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5 -One or more compounds in the group consisting of pentanediol, 2-ethyl-2-butyl-1,3-propanediol, and 2,4-diethyl-1,5-pentanediol.

The number average molecular weight of the polyester polyol (a1) is preferably less than 2,800, more preferably in the range of 300 to 2,500, and still more preferably, in terms of obtaining further excellent initial adhesive strength and flexibility. It is in the range of 600 to 2,200. In addition, the number average molecular weight of the polyester polyol (a1) represents a value measured by a gel permeation chromatography (Gel Permeation Chromatography, GPC) method.

The content of the polyester polyol (a1) is preferably 5 mass in the polyol (A) in terms of obtaining further excellent initial adhesive strength, coating suitability, and flexibility. The range of% to 80% by mass, more preferably the range of 10% to 75% by mass, and still more preferably the range of 15% to 70% by mass.

In order to obtain excellent low viscosity, flexibility and hydrolysis resistance, the polyether polyol (a2) is an essential component. As the polyether polyol (a2), for example, polyoxyalkylene polyol can be used; one or two or more compounds having two or more active hydrogen atoms are used as the initiator, and alkylene oxide, etc. Ring-opening polymerization of cyclic ether, etc.

The number of carbon atoms of the cyclic ether is preferably 2-10, more preferably 2-6, and still more preferably 2-4. The hydrogen atom contained in the cyclic ether may be substituted with a halogen atom. As the cyclic ether, one kind or two or more kinds may be used. For example, ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, styrene oxide, and Chlorohydrin, tetrahydrofuran, alkylated tetrahydrofuran, etc.

As the initiator, one kind or two or more kinds can be used, for example, ethylene glycol, diethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol can be used , 1,6-hexanediol, neopentyl glycol, water and other compounds with two active hydrogen atoms; glycerol, diglycerol, trimethylolethane, trimethylolpropane, hexanetriol, monoethanolamine, Compounds having three or more active hydrogen atoms, such as diethanolamine, triethanolamine, ethylenediamine, pentaerythritol, sugars, and the like.

As the polyether polyol (a2), it is preferable to use polyoxypropylene glycol and/or in terms of obtaining further excellent low viscosity, flexibility, coating adaptability, and hydrolysis resistance. Polytetramethylene glycol, more preferably polyoxypropylene glycol.

The number average molecular weight of the polyether polyol (a2) is preferably less than 2,800 in terms of obtaining further excellent low viscosity, flexibility, coating adaptability, and hydrolysis resistance. It is the range of 300-2,500, More preferably, it is the range of 600-2,200. In addition, the number average molecular weight of the polyether polyol (a2) represents a value measured by a gel permeation chromatography (GPC) method.

The content of the polyether polyol (a2) is preferably 5 mass% in the polyol (A) in terms of obtaining further excellent low viscosity, flexibility, and hydrolysis resistance. It is the range of -80 mass %, More preferably, it is the range of 10 mass%-75 mass %, More preferably, it is the range of 15 mass%-70 mass %.

The aromatic polyester polyol (a3) is an essential component in terms of obtaining excellent initial adhesive strength and flexibility. As the aromatic polyester polyol (a3), for example, a reaction product of a compound having a hydroxyl group and a polybasic acid containing an aromatic polybasic acid; a reaction product of an aromatic compound having two or more hydroxyl groups and a polybasic acid can be used; A reaction product of an aromatic compound having two or more hydroxyl groups and a polybasic acid containing an aromatic polybasic acid, and the like.

As the compound having a hydroxyl group, for example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptane can be used. Glycol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, diethylene glycol, triethylene glycol, tetraethylene glycol Alcohol, 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, Aliphatic compounds such as 5-pentanediol, trimethylolethane, trimethylolpropane, and pentaerythritol; cyclopentanediol, cyclohexanediol, cyclohexane dimethanol, hydrogenated bisphenol A, these Alicyclic compounds such as oxane adducts, etc. These compounds may be used alone, or two or more of them may be used in combination.

As the aromatic compound having two or more hydroxyl groups, for example, bisphenol A, bisphenol F, and these alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adducts can be used Wait. These compounds may be used alone, or two or more of them may be used in combination. Among these, it is preferable to use an alkylene oxide adduct of bisphenol A as the number of added moles of the alkylene oxide in terms of obtaining further excellent initial adhesive strength and flexibility. It is preferably in the range of 1 mol to 10 mol.

As the aromatic polybasic acid, for example, phthalic acid, isophthalic acid, terephthalic acid, phthalic anhydride, etc. can be used. As other polybasic acids, for example, oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, 1,12-dodecane dicarboxylic acid, etc. can be used. These polybasic acids may be used alone, or two or more of them may be used in combination. As the aromatic polybasic acid, it is preferable to use one selected from the group consisting of phthalic acid, isophthalic acid, terephthalic acid, and phthalic acid in terms of obtaining further excellent initial adhesion strength and flexibility. One or more compounds in the group consisting of formic anhydride.

As other polybasic acids, for example, succinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedioic acid, dodecanedioic acid, two Decanedioic acid, citraconic acid, itaconic acid, citraconic anhydride, itaconic anhydride, etc.

The number average molecular weight of the aromatic polyester polyol (a3) is preferably less than 2,800, more preferably in the range of 300 to 2,500, in terms of obtaining further excellent initial bonding strength and flexibility. More preferably, it is the range of 600-2,200. In addition, the number average molecular weight of the aromatic polyester polyol (a3) represents a value measured by a gel permeation chromatography (GPC) method.

As the content rate of the aromatic polyester polyol (a3), in terms of obtaining further excellent initial adhesive strength, flexibility, and coating suitability, among the polyol (A), it is preferably The range of 1% by mass to 49% by mass, more preferably the range of 4% by mass to 47% by mass, and still more preferably the range of 8% by mass to 45% by mass.

Furthermore, in the present invention, in order to satisfy all the problems to be solved by the invention of this application, the total amount of the polyester polyol (a1) and the polyether polyol (a2) must be more than the total amount used. The amount of aromatic polyester polyol (a3) used is described. As the ratio of the total usage amount of the polyester polyol (a1) and the polyether polyol (a2) to the usage amount of the aromatic polyester polyol (a3) [((a1)+(a2) )/(A3)], preferably in the range of 99/1 to 51/49, more preferably in the range of 95/5 to 53/47, and still more preferably in the range of 90/10 to 55/45.

In addition, the mass ratio [(a1)/(a2)] of the polyester polyol (a1) to the polyether polyol (a2) is preferably in the range of 90/10 to 10/90, more preferably It is the range of 85/15-15/85, More preferably, it is the range of 80/20-20/80.

As the polyol (A), in addition to the polyol (a1) to the polyol (a3), other polyols may be used as needed.

As the other polyols, for example, polyester polyols, polycarbonate polyols, polyacrylic polyols, polybutadiene polyols, and hydrogenated polybutadiene polyols other than (a1) and (a3) can be used. Alcohol etc. These polyols may be used singly, or two or more of them may be used in combination.

As the total amount of the polyester polyol (a1), the polyether polyol (a2), and the aromatic polyester polyol (a3), in the polyol (A), it is preferably 50 Mass% or more, more preferably 70 mass% or more, still more preferably 80 mass% or more, particularly preferably 90 mass% or more.

As the polyisocyanate (B), for example, polymethylene polyphenyl polyisocyanate, diphenylmethane diisocyanate, carbodiimide modified diphenylmethane diisocyanate isocyanate, phenylene diisocyanate, Aromatic polyisocyanates such as toluene diisocyanate and naphthalene diisocyanate; hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate Aliphatic polyisocyanates such as isocyanate and tetramethylxylylene diisocyanate, or alicyclic polyisocyanates, etc. Among these, in terms of obtaining further excellent reactivity and final bonding strength, it is preferable to use an aromatic polyisocyanate, and more preferably diphenylmethane diisocyanate.

In addition, the amount of the polyisocyanate (B) used is preferably 5% by mass in the raw material of the urethane prepolymer (i) in terms of obtaining more excellent adhesive strength. It is in the range of -60% by mass, more preferably in the range of 15% by mass to 50% by mass.

The urethane prepolymer (i) is obtained by reacting the polyol (A) with the polyisocyanate (B), and has a polymer end or molecule capable of interacting with the air Neutralizes or forms a cross-linked isocyanate group by reacting with moisture in the frame or adherend to which the urethane prepolymer is applied.

As a method of producing the urethane prepolymer (i), for example, it can be produced by dropping the polyol (A) into a reaction vessel containing the polyisocyanate (B). ), and then heating and reacting under the condition that the isocyanate group of the polyisocyanate (B) is excessive with respect to the hydroxyl group of the polyol (A).

The amount of urethane bonds of the urethane prepolymer (i) is preferably 0.5 mol in terms of obtaining further excellent initial adhesion strength, flexibility, and low viscosity. /kg to 3 mol/kg, more preferably 0.9 mol/kg to 2.7 mol/kg, still more preferably 1.1 mol/kg to 2.4 mol/kg.

As the equivalent ratio of the isocyanate group of the polyisocyanate (B) to the hydroxyl group of the polyol (A) when the urethane prepolymer (i) is produced ([isocyanate group/ Hydroxy]), in terms of obtaining further excellent initial adhesive strength, flexibility, and low viscosity, the range is preferably 1.1 to 1.5, and more preferably 1.15 to 1.45.

As the isocyanate group content of the urethane prepolymer (i) (hereinafter, abbreviated as "NCO%"), further excellent initial adhesive strength, flexibility, and low viscosity can be obtained. In other words, it is preferably in the range of 1% by mass to 4% by mass, and more preferably in the range of 1.2% by mass to 3.5% by mass. Furthermore, the NCO% of the urethane prepolymer (i) represents a value obtained by measuring according to Japanese Industrial Standards (JIS) K1603-1:2007 and by potentiometric titration.

The moisture-curable polyurethane hot-melt resin composition of the present invention may contain other additives as needed in addition to the urethane prepolymer (i).

As the other additives, for example, antioxidants, tackifiers, plasticizers, stabilizers, fillers, dyes, pigments, fluorescent whitening agents, silane coupling agents, waxes, etc. can be used. These additives may be used alone, or two or more of them may be used in combination.

As a method of obtaining a cured film of the moisture-curing polyurethane hot-melt resin composition, for example, the following method can be cited: the moisture-curing polyurethane hot-melt resin composition is applied to It is melted at 50℃～130℃, then coated on the base material and cured by moisture.

As the substrate, for example, acrylic resins, urethane resins, silicon resins, epoxy resins, fluorine resins, polystyrene resins, polyester resins, polycure resins, etc. can be used. Polyarylate resin, polyvinyl chloride resin, polyvinylidene chloride, cycloolefin resin, polyolefin resin, polyimide resin, alicyclic polyimide resin, cellulose resin, polycarbonate Polycarbonate (PC), Polybutylene Terephthalate (PBT), Modified Polyphenyl Ether (PPE), Polyethylene Naphthalate (PEN), Poly Polyethylene Terephthalate (PET), lactic acid polymer, Acrylonitrile Butadiene Styrene (ABS) resin, Acrylonitrile Styrene (AS) resin and other resin films ; Medium Density Fiberboard (MDF), plywood, plastic plywood (particle board) and other wooden substrates; non-woven fabrics, woven fabrics, woven fabrics and other fiber substrates. The substrate may also be subjected to corona treatment, plasma treatment, primer treatment, etc. as needed.

As a method of applying the moisture-curable polyurethane hot-melt resin composition, for example, the use of a roll coater, spray coater, T-die coater, knife coater, Methods such as missing corner wheel coater.

After the coating, the final bonding strength can be obtained by aging at a temperature of 20°C to 80°C and a relative humidity of 50% to 90% for 0.5 to 3 days.

As the moisture-curing polyurethane hot-melt resin composition of the present invention, in terms of obtaining further excellent initial adhesive strength, the storage elasticity is the melt viscoelasticity at 20°C before curing The coefficient (G') is preferably 0.1 MPa or more, preferably in the range of 0.2 MPa to 1,000 MPa, more preferably in the range of 0.3 MPa to 500 MPa.

Furthermore, the storage elastic coefficient (G') represents the following storage elastic coefficient (G'): the moisture-curable polyurethane hot-melt resin composition is melted at 110°C for 1 hour, and then 10 ml is sampled , Placed on the parallel plate of the melt viscoelasticity measuring device (Anton Paar (Anton Paar) "MCR-302") parallel plate, from 110 ℃ to 10 ℃ with a cooling rate of 1 ℃/min, frequency 1 Hz for melt viscoelasticity The storage elastic coefficient (G') at 20°C during the measurement.

In addition, the Young's coefficient of the cured film of the present invention is preferably 20 MPa or less, more preferably in the range of 0.5 MPa to 15 MPa, and still more preferably 1 MPa in terms of obtaining more excellent flexibility. ～10 MPa range.

In addition, the Young’s coefficient represents the following value: after the moisture-curing polyurethane hot-melt resin composition is melted at 110°C for 1 hour, the mold release-treated polyethylene terephthalate On the ester substrate, apply it with a knife coater so that the cured film thickness becomes 100 μm, and leave it for 3 days to obtain a cured film. The cured film is peeled from the mold release PET, and a No. 2 dumbbell is used. Press processing and use the resultant as a test piece. For this test piece, a Tensilon tensile testing machine ("RTM-100" manufactured by Orientec Co., Ltd.) was used at 25°C. Under the environment, the tensile test is performed at a crosshead speed: 200 mm/min, and the value is measured based on the origin of the graph at this time and the stress at an elongation of 2.5%.

As described above, the moisture-curable polyurethane hot-melt resin composition of the present invention is excellent in low viscosity, initial adhesive strength, flexibility, coating suitability, and hydrolysis resistance. Therefore, the moisture-curing polyurethane hot-melt resin composition of the present invention can be particularly suitably used for fiber applications. [Example]

Hereinafter, the present invention will be further described in detail through examples.

[Example 1] Put 35 parts by mass of aliphatic polyester polyol (derived from the reaction of butanediol and adipic acid into a four-necked flask including a thermometer, agitator, inert gas inlet and reflux cooler, number average molecular weight: 1,000, Hereinafter referred to as "BG/AA"), 35 parts by mass of polyoxypropylene glycol (number average molecular weight: 1,000, hereafter referred to as "PPG"), 30 parts by mass of aromatic polyester polyol (using neopentyl glycol It is obtained by reacting with o-phthalic acid, number average molecular weight: 1,000, hereinafter abbreviated as "NPG/PA1000"), heated at 90°C under reduced pressure, and dehydrated until the moisture content becomes 0.05 Less than mass%. Then, the temperature in the container was cooled to 60°C, and 33 parts by mass of 4,4'-diphenylmethane diisocyanate (hereinafter abbreviated as "MDI") was added, the temperature was raised to 110°C, and the reaction was carried out for about 3 hours until the isocyanate group The content rate becomes constant, the urethane prepolymer (i-1) having an isocyanate group is obtained, and a moisture-curable polyurethane hot-melt resin composition is obtained. The NCO% of the urethane prepolymer (i-1) was 1.7% by mass, the amount of urethane bonds was 1.50 mol/kg, and the [NCO/OH] during synthesis was 1.32.

[Example 2] Put 25 parts by mass of BG/AA, 50 parts by mass of PPG, and 25 parts by mass of NPG/PA1000 into a four-necked flask including thermometer, stirrer, inert gas inlet and reflux cooler, and heat under reduced pressure at 90°C By this, it is dehydrated until the moisture content becomes 0.05% by mass or less. Then, 33 parts by mass of MDI was added, the temperature was raised to 110°C, and the reaction was carried out for about 3 hours until the isocyanate group content became constant to obtain a urethane prepolymer (i-2) having an isocyanate group, thereby obtaining moisture Hardening polyurethane hot-melt resin composition. The NCO% of the urethane prepolymer (i-2) was 1.7% by mass, the amount of urethane bonds was 1.50 mol/kg, and the [NCO/OH] during synthesis was 1.32.

[Example 3] Put 35 parts by mass of aliphatic polyester polyol (obtained by the reaction of neopentyl glycol and adipic acid in a four-necked flask including a thermometer, agitator, inert gas inlet and reflux cooler, number average molecular weight: 1,000 , Hereinafter abbreviated as "NPG/AA"), 35 parts by mass of PPG, 30 parts by mass of aromatic polyester polyol (resulting from the reaction of 6 mol adduct of bisphenol A with propylene oxide and sebacic acid , Number average molecular weight: 1,000, hereinafter abbreviated as "BISA6PO/SEBA"), heat under reduced pressure at 90°C, thereby dehydrating until the moisture content becomes 0.05% by mass or less. Then, the temperature in the container was cooled to 60°C, 33 parts by mass of MDI was added, the temperature was raised to 110°C, and the reaction was carried out for about 3 hours until the isocyanate group content became constant, and a urethane prepolymer having isocyanate groups was obtained. (I-3), thereby obtaining a moisture-curing polyurethane hot-melt resin composition. The NCO% of the urethane prepolymer (i-3) was 1.7% by mass, the amount of urethane bonds was 1.50 mol/kg, and the [NCO/OH] during synthesis was 1.32.

[Example 4] Put 20 parts by mass of NPG/AA, 40 parts by mass of PPG, and 40 parts by mass of BISA6PO/SEBA into a four-necked flask including a thermometer, stirrer, inert gas inlet and reflux cooler, and heat under reduced pressure at 90°C By this, it is dehydrated until the moisture content becomes 0.05% by mass or less. Then, the temperature in the container was cooled to 60°C, 33 parts by mass of MDI was added, the temperature was raised to 110°C, and the reaction was carried out for about 3 hours until the isocyanate group content became constant, and a urethane prepolymer having isocyanate groups was obtained. (I-4), thereby obtaining a moisture-curing polyurethane hot-melt resin composition. The NCO% of the urethane prepolymer (i-4) was 1.7% by mass, the amount of urethane bonds was 1.50 mol/kg, and the [NCO/OH] during synthesis was 1.32.

[Example 5] Put 55 parts by mass of NPG/AA, 30 parts by mass of PPG, and 15 parts by mass of NPG/PA1000 into a four-necked flask including thermometer, stirrer, inert gas inlet and reflux cooler, and heat under reduced pressure at 90°C By this, it is dehydrated until the moisture content becomes 0.05% by mass or less. Then, the temperature in the container was cooled to 60°C, 33 parts by mass of MDI was added, the temperature was raised to 110°C, and the reaction was carried out for about 3 hours until the isocyanate group content became constant, and a urethane prepolymer having isocyanate groups was obtained. (I-5), thereby obtaining a moisture-curing polyurethane hot-melt resin composition. The NCO% of the urethane prepolymer (i-5) was 1.7% by mass, the amount of urethane bonds was 1.50 mol/kg, and the [NCO/OH] during synthesis was 1.32.

[Example 6] Put 30 parts by mass of aliphatic polyester polyol (derived from the reaction of diethylene glycol and adipic acid in a four-necked flask including a thermometer, agitator, inert gas inlet and reflux cooler, number average molecular weight: 1000 , Hereinafter abbreviated as "DEG/AA"), 30 parts by mass of PPG, 40 parts by mass of aromatic polyester polyol (resulting from the reaction of neopentyl glycol and o-phthalic acid, the quantity Average molecular weight: 2,000, hereinafter abbreviated as "NPG/PA2000"), and heat under reduced pressure at 90°C to dehydrate until the moisture content becomes 0.05% by mass or less. Then, the temperature in the container was cooled to 60°C, 28 parts by mass of MDI were added, the temperature was raised to 110°C, and the reaction was carried out for about 3 hours until the isocyanate group content became constant, and a urethane prepolymer having isocyanate groups was obtained. (I-6), thereby obtaining a moisture-curing polyurethane hot-melt resin composition. The NCO% of the urethane prepolymer (i-6) was 1.8% by mass, the amount of urethane bonds was 1.25 mol/kg, and the [NCO/OH] during synthesis was 1.40.

[Example 7] Put 20 parts by mass of DEG/AA, 50 parts by mass of PPG, and 30 parts by mass of aromatic polyester polyol (making ethylene glycol and O-phthalic acid (o-phthalic acid) reaction, number average molecular weight: 600, hereinafter abbreviated as "EG/PA600"), heated at 90°C under reduced pressure, thereby dehydrating until the moisture content becomes 0.05 mass %the following. Then, the temperature in the container was cooled to 60°C, 38 parts by mass of MDI were added, the temperature was raised to 110°C, and the reaction was carried out for about 3 hours until the isocyanate group content became constant, and a urethane prepolymer having isocyanate groups was obtained. (I-7), thereby obtaining a moisture-curing polyurethane hot-melt resin composition. The NCO% of the urethane prepolymer (i-7) was 1.6% by mass, the amount of urethane bonds was 1.74 mol/kg, and the [NCO/OH] during synthesis was 1.27.

[Comparative Example 1] Put 15 parts by mass of BG/AA, 15 parts by mass of PPG, and 70 parts by mass of NPG/PA into a four-necked flask including thermometer, stirrer, inert gas inlet and reflux cooler, and heat under reduced pressure at 90°C By this, it is dehydrated until the moisture content becomes 0.05% by mass or less. Then, the temperature in the container was cooled to 60°C, 35 parts by mass of MDI was added, the temperature was raised to 110°C, and the reaction was carried out for about 3 hours until the isocyanate group content became constant, and a urethane prepolymer having isocyanate groups was obtained. (I-R1), thereby obtaining a moisture-curing polyurethane hot-melt resin composition. The NCO% of the urethane prepolymer (i-R1) is 2.2% by mass, the amount of urethane bonds is 1.48 mol/kg, and the [NCO/OH] during synthesis is 1.40.

[Comparative Example 2] Put 70 parts by mass of PPG and 30 parts by mass of NPG/PA1000 into a four-necked flask including a thermometer, agitator, an inert gas inlet, and a reflux cooler, and heat it under reduced pressure at 90°C to achieve dehydration to moisture content. Be 0.05% by mass or less. Then, the temperature in the container was cooled to 60°C, 33 parts by mass of MDI was added, the temperature was raised to 110°C, and the reaction was carried out for about 3 hours until the isocyanate group content became constant, and a urethane prepolymer having isocyanate groups was obtained. (I-R2), thereby obtaining a moisture-curing polyurethane hot-melt resin composition. The NCO% of the urethane prepolymer (i-R2) is 1.7% by mass, the amount of urethane bonds is 1.50 mol/kg, and the [NCO/OH] during synthesis is 1.32.

[Comparative Example 3] Put 70 parts by mass of BG/AA and 30 parts by mass of NPG/PA1000 into a four-necked flask including a thermometer, agitator, an inert gas inlet and a reflux cooler, and heat under reduced pressure at 90°C, thereby dehydrating to moisture The content rate is 0.05% by mass or less. Then, the temperature in the container was cooled to 60°C, 33 parts by mass of MDI was added, the temperature was raised to 110°C, and the reaction was carried out for about 3 hours until the isocyanate group content became constant, and a urethane prepolymer having isocyanate groups was obtained. (I-R3), thereby obtaining a moisture-curing polyurethane hot-melt resin composition. The NCO% of the urethane prepolymer (i-R3) was 1.7% by mass, the amount of urethane bonds was 1.50 mol/kg, and the [NCO/OH] during synthesis was 1.32.

[Measurement method of number average molecular weight] In the examples and comparative examples, the number average molecular weight of polyols and the like represents a value measured by a gel permeation chromatography (GPC) method under the following conditions.

Measuring device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Co., Ltd.) String: The following pipe strings manufactured by Tosoh Co., Ltd. are connected in series and used. "TSKgel G5000" (7.8 mmI.D.×30 cm)×1 "TSKgel G4000" (7.8 mmI.D.×30 cm)×1 "TSKgel G3000" (7.8 mmI.D.×30 cm)×1 "TSKgel G2000" (7.8 mmI.D.×30 cm)×1 Detector: RI (differential refractometer) Column temperature: 40℃ Eluent: Tetrahydrofuran (Tetrahydrofuran, THF) Flow rate: 1.0 mL/min Injection volume: 100 μL (a tetrahydrofuran solution with a sample concentration of 0.4% by mass) Standard sample: Use the following standard polystyrene to make a standard curve.

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

[Method of Measuring Viscosity] The moisture-curing polyurethane hot-melt resin composition obtained in the examples and comparative examples was melted at 120°C for 1 hour, and then 1 ml was sampled, and the cone-plate viscometer (40P) Cone, rotor speed: 50 rpm) to measure the melt viscosity, and evaluate the low viscosity as follows. "○": Less than 30,000 mPa·s "×": 30,000 mPa·s or more

[Measuring method of initial adhesive strength] The moisture-curable polyurethane hot-melt resin compositions obtained in the Examples and Comparative Examples were melted at a temperature of 120°C for 1 hour, respectively. Using an applicator, the adhesive was applied to the polyethylene terephthalate sheet so that the thickness would be 100 μm. A polyethylene terephthalate sheet was stuck on the coating layer, and pressure-bonded with a pressure-bonding roller. Five minutes after crimping, the adhesion strength (N/25 mm) was measured using the precision universal testing machine "AG-10NX" manufactured by Shimadzu Corporation, and the initial adhesion strength was evaluated as follows. "○": Adhesive strength is 15 (N/25 mm) or more. "×": Adhesion strength is less than 15 (N/25 mm).

[Method of evaluating flexibility] The moisture-curing polyurethane hot-melt resin composition obtained in the examples and comparative examples was melted at 110°C for 1 hour, and then, on the polyester non-woven fabric, a knife coater was used to harden The latter was applied so that the film thickness became 100 μm, and it was left for 3 days to obtain a hardened film. Based on the touch, the softness was evaluated as follows. "○": Rich in flexibility. "×": Gives a hard impression.

[Evaluation method of coating suitability] The moisture-curing polyurethane hot-melt resin composition obtained in the examples and comparative examples was melted at 110°C for 1 hour, and then a dressing was applied on a polyethylene terephthalate sheet The device was coated so that the thickness was 100 μm, and the coating suitability was evaluated as follows. "○": The coating is uneven and there are few coating streaks. "×": The coating is uneven and there are many coating streaks.

[Evaluation method of hydrolysis resistance] The moisture-curing polyurethane hot-melt resin composition obtained in the Examples and Comparative Examples was melted at 110°C for 1 hour, and then, on a release paper, an applicator was used to make the thickness 100 μm. The method is applied and left for 3 days to obtain a hardened film. The obtained cured film was cured for 3 weeks under the conditions of 70°C and 95% humidity. According to JIS-K7312 (1996), using the "autograph AG-I" manufactured by Shimadzu Corporation, the tensile strength of the film is measured before and after curing, and the relative value after curing when the value before curing is 100 When the value is 50 or more, it is evaluated as "○", and when it is less than 50, it is evaluated as "×".

[Table 1] Example 1 Example 2 Example 3 Example 4 Urethane prepolymer (i) (I-1) (I-2) (I-3) (I-4) Polyester polyol with adipic acid as raw material (a1) BG/AA (parts by mass) 35 25 NPG/AA (parts by mass) 35 20 DEG/AA (parts by mass) Polyether polyol (a2) PPG (parts by mass) 35 50 35 40 Aromatic polyester polyol (a3) NPG/PA1000 (parts by mass) 30 25 NPG/PA2000 (parts by mass) EG/PA600 (parts by mass) SEBA/BISA6PO (parts by mass) 30 40 Polyisocyanate (B) MDI (parts by mass) 33 33 33 33 The molar ratio of (A) and (B) [NCO/OH] 1.32 1.32 1.32 1.32 The amount of urethane bond of urethane prepolymer (i) (mol/kg) 1.50 1.50 1.50 1.50 NCO% (mass%) of urethane prepolymer (i) 1.7 1.7 1.7 1.7 Evaluation of low viscosity ○ ○ ○ ○ Evaluation of initial bonding strength ○ ○ ○ ○ Evaluation of flexibility ○ ○ ○ ○ Evaluation of coating suitability ○ ○ ○ ○ Evaluation of hydrolysis resistance ○ ○ ○ ○

[Table 2] Example 5 Example 6 Example 7 Urethane prepolymer (i) (I-5) (I-6) (I-7) Polyester polyol with adipic acid as raw material (a1) BG/AA (parts by mass) NPG/AA (parts by mass) 55 DEG/AA (parts by mass) 30 20 Polyether polyol (a2) PPG (parts by mass) 30 30 50 Aromatic polyester polyol (a3) NPG/PA1000 (parts by mass) 15 NPG/PA2000 (parts by mass) 40 EG/PA600 (parts by mass) 30 SEBA/BISA6PO (parts by mass) Polyisocyanate (B) MDI (parts by mass) 33 28 38 The molar ratio of (A) and (B) [NCO/OH] 1.32 1.40 1.27 The amount of urethane bond of urethane prepolymer (i) (mol/kg) 1.50 1.25 1.74 NCO% (mass%) of urethane prepolymer (i) 1.7 1.8 1.6 Evaluation of low viscosity ○ ○ ○ Evaluation of initial bonding strength ○ ○ ○ Evaluation of flexibility ○ ○ ○ Evaluation of coating suitability ○ ○ ○ Evaluation of hydrolysis resistance ○ ○ ○

[table 3] Comparative example 1 Comparative example 2 Comparative example 3 Urethane prepolymer (i) (I-R1) (I-R2) (I-R3) Polyester polyol with adipic acid as raw material (a1) BG/AA (parts by mass) 15 70 NPG/AA (parts by mass) DEG/AA (parts by mass) Polyether polyol (a2) PPG (parts by mass) 15 70 Aromatic polyester polyol (a3) NPG/PA1000 (parts by mass) 70 30 30 NPG/PA2000 (parts by mass) EG/PA600 (parts by mass) SEBA/BISA6PO (parts by mass) Polyisocyanate (B) MDI (parts by mass) 35 35 35 The molar ratio of (A) and (B) [NCO/OH] 1.40 1.40 1.40 The amount of urethane bond of urethane prepolymer (i) (mol/kg) 1.48 1.48 1.48 NCO% (mass%) of urethane prepolymer (i) 2.2 2.2 2.2 Evaluation of low viscosity X ○ ○ Evaluation of initial bonding strength ○ ○ ○ Evaluation of flexibility X ○ ○ Evaluation of coating suitability X X ○ Evaluation of hydrolysis resistance ○ ○ X

It can be seen that the moisture-curing polyurethane hot-melt resin composition of the present invention is excellent in low viscosity, initial adhesive strength, flexibility, coating suitability, and hydrolysis resistance.

On the other hand, in Comparative Example 1, the amount of the aromatic polyester polyol used was more than the range specified in the present invention, and the low viscosity, flexibility, and coating adaptability were poor.

In Comparative Example 2, the polyester polyol (a1) was not used, and the coating adaptability was poor.

In Comparative Example 3, the polyether polyol (a2) was not used, and the hydrolysis resistance was poor.

no

no

Claims (4)

A moisture-curing polyurethane hot-melt resin composition, containing a urethane prepolymer (i) with isocyanate groups using polyol (A) and polyisocyanate (B) as raw materials, and The moisture-curing polyurethane hot-melt resin composition is characterized by: The polyol (A) contains adipic acid-based polyester polyol (a1), polyether polyol (a2) and aromatic polyester polyol (a3), The total usage amount of the polyester polyol (a1) and the polyether polyol (a2) is more than the usage amount of the aromatic polyester polyol (a3). The moisture-curing polyurethane hot-melt resin composition according to claim 1, wherein the urethane prepolymer (i) has a urethane bond amount of 0.5 mol/ kg～3 mol/kg range. The moisture-curable polyurethane hot-melt resin composition according to claim 1 or claim 2, wherein the molar ratio of the polyol (A) to the polyisocyanate (B) [NCO /OH] is in the range of 1.1 to 1.5. The moisture-curable polyurethane hot-melt resin composition according to any one of claims 1 to 3, wherein the isocyanate group of the urethane prepolymer (i) contains The rate is in the range of 1% by mass to 4% by mass.