JP2022189479A - Moisture-curable hot-melt adhesive - Google Patents

Abstract

To provide a moisture-curable hot-melt adhesive which is excellent in resin adhesiveness and wet heat adhesiveness.SOLUTION: A moisture-curable hot-melt adhesive contains crystalline polyester polyol which is a condensation polymer of a polycarboxylic acid having predetermined carbon atoms and polyol having predetermined carbon atoms, microcrystalline polyester polyol having a predetermined number average molecular weight, amorphous polyester polyol having a predetermined number average molecular weight and polyol containing polyether polyol having a predetermined number average molecular weight, and an urethane prepolymer that is a reactant with a polyisocyanate compound and has an isocyanate group at a terminal, wherein the polyol contains the crystalline polyester polyol, the microcrystalline polyester polyol, the amorphous polyester polyol and the polyester polyol each in prescribed amounts.SELECTED DRAWING: None

Description

The present invention relates to a moisture-curable hot-melt adhesive.

2. Description of the Related Art Conventionally, a decorative sheet is attached to the surface of a base material such as furniture, exterior materials, and interior materials using a moisture-curable hot-melt adhesive to impart design.

Wood has traditionally been widely used for base materials such as interior materials, but in recent years, synthetic resin base materials have been increasingly used instead of wood.

Patent Document 1 discloses 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 an isocyanate compound (b), wherein the polyol (a) is , an alicyclic polycarbonate polyol (a-1), a crystalline polyester polyol (a-2), and a polyether polyol (a-3), wherein the isocyanate compound (b) is a diisocyanate (b-1) , a polymethylene polyphenyl isocyanate compound (b-2), and an isocyanurate compound (b-3).

JP 2020-97653 A

However, the moisture-curable hot-melt adhesive has a problem of low adhesion to synthetic resin substrates.

Furthermore, in recent years, decorative sheets have been attached to substrates used around water such as bathrooms using moisture-curable hot-melt adhesives. There is a problem that the decorative sheet peels off from the base material during use because of its low water resistance (adhesiveness under wet heat).

The present invention has excellent adhesiveness (resin adhesiveness) to synthetic resin substrates, and maintains excellent adhesiveness even when used in an atmosphere where humidity tends to increase at high temperatures ( To provide a moisture-curing hot-melt adhesive capable of moist heat adhesion.

The moisture-curable hot-melt adhesive of the present invention is
A urethane prepolymer that is a reaction product of a polyol and a polyisocyanate compound and has an isocyanate group at the end,
The above polyols are a first polyol containing a microcrystalline polyester polyol having a number average molecular weight of 3000 to 6000 and a liquid polyester polyol having a number average molecular weight of 1000 to 6000, and a polyether polyol having a number average molecular weight of 500 to 7000. and at least one second polyol selected from the group consisting of castor oil polyols,
The polyisocyanate compound includes a first polyisocyanate compound containing diisocyanate and polymethylene polyphenyl isocyanate, and at least one second polyisocyanate compound selected from the group consisting of isocyanurate compounds and biuret-type polyisocyanates.

The moisture-curable hot-melt adhesive of the present invention has excellent adhesiveness to synthetic resin substrates, and exhibits excellent adhesiveness even when used in an atmosphere where humidity tends to increase. to maintain

The moisture-curable hot-melt adhesive of the present invention contains a urethane prepolymer which is a reaction product of a polyol containing a prescribed polyol and a prescribed polyisocyanate compound and has isocyanate groups at its terminals. The urethane prepolymer is cured by a cross-linking reaction caused by air and/or moisture contained in the base material.

The reaction between the polyol and the polyisocyanate compound may be carried out in a general manner. For example, it can be obtained by charging a polyisocyanate compound into a reaction vessel, adding polyols from which moisture has been removed in advance separately, or after mixing them together with additives, and dropping them, and allowing hydroxyl groups and isocyanate groups to react in a heated state. . Alternatively, a polyol, an additive, and the like may be charged into a reaction vessel, heated and melted to disperse, water is removed, and then a polyisocyanate compound is charged to react hydroxyl groups and isocyanate groups. The urethane prepolymer can be generally produced without a solvent, but it can also be produced in a solvent that does not inhibit the reaction. Specific examples of solvents include butyl acetate, methyl ethyl ketone, and toluene. A urethanization catalyst can be used as necessary in the reaction between the hydroxyl groups of the polyol and the isocyanate groups of the polyisocyanate compound. The urethanization catalyst is not particularly limited, and examples thereof include triethylamine, triethylenediamine, N-methylmorpholine, potassium acetate, zinc stearate, tin octoate, and dibutyltin dilaurate. The urethane or catalyst may be used alone or in combination of two or more.

In the reaction between the polyol and the polyisocyanate compound, the ratio of the number of moles of hydroxyl groups in the polyol to the number of moles of isocyanate groups in the polyisocyanate compound (number of moles of isocyanate groups/number of moles of hydroxyl groups) is 1.3 to 4.0 is preferred, and 1.5 to 3.0 is more preferred. When the molar ratio is 1.5 or more, the moisture-curable hot-melt adhesive is improved in coatability. When the molar ratio is 3.0 or less, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved.

[Polyol]
The urethane prepolymer contained in the moisture-curable hot-melt adhesive is a reaction product of polyol (A) containing a predetermined polyol and polyisocyanate compound (B). The urethane prepolymer has isocyanate groups at the ends of its molecules, and preferably has isocyanate groups at both ends of the molecule.

The polyol (A) is selected from the group consisting of a first polyol containing a microcrystalline polyester polyol (A1) and a liquid polyester polyol (A2), a polyether polyol (A3) and a castor oil polyol (A6), which will be described later. and at least one second polyol.

Polyol (A) contains microcrystalline polyester polyol (A1) and liquid polyester polyol (A2) as essential components, and contains either one or both of polyether polyol (A3) and castor oil polyol (A6).

Polyol (A) may further contain crystalline polyester polyol (A4) and polycarbonate polyol (A5).

In the polyol (A), the total amount of the microcrystalline polyester polyol (A1), the liquid polyester polyol (A2) and the second polyol is preferably 50% by mass or more, more preferably 60% by mass or more, and 70% by mass or more. It is more preferably 80% by mass or more, more preferably 90% by mass or more, and more preferably 100% by mass.

In the polyol (A), the total amount of the microcrystalline polyester polyol (A1), the liquid polyester polyol (A2), the second polyol, the crystalline polyester polyol (A4) and the polycarbonate polyol (A5) is preferably 50% by mass or more. , more preferably 60% by mass or more, more preferably 70% by mass or more, more preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass.

[First polyol]
The first polyol includes a microcrystalline polyester polyol (A1) and a liquid polyester polyol (A2).

[Microcrystalline polyester polyol (A1)]
Polyol (A) contains a microcrystalline polyester polyol (A1) having a number average molecular weight of 3000 to 6000 (hereinafter sometimes simply referred to as "microcrystalline polyester polyol (A1)"). Microcrystalline polyester polyol (A1) is a condensation polymer of polycarboxylic acid and polyol. That is, the microcrystalline polyester polyol (A1) is a polymer obtained by condensation polymerization of a polycarboxylic acid and a polyol through an ester reaction between the carboxyl groups of the polycarboxylic acid and the hydroxyl groups of the polyol.

Polycarboxylic acids are not particularly limited, and examples include terephthalic acid, isophthalic acid, 1,5-naphthalic acid, 2,6-naphthalic acid, cyclohexanedicarboxylic acid, cyclopentanedicarboxylic acid, succinic acid, glutaric acid, adipic acid, Examples include pimelic acid, suberic acid, azelaic acid, sebacic acid, decamethylenedicarboxylic acid, dodecamethylenedicarboxylic acid, etc. Preferred are adipic acid and terephthalic acid, and more preferred is adipic acid. In addition, polycarboxylic acid may be used independently or 2 or more types may be used together.

Polyols are not particularly limited, and examples include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 1 ,8-octanediol, 1,10-decanediol, diethylene glycol, cyclohexanediol and the like, preferably 1,6-hexanediol and ethylene glycol, more preferably 1,6-hexanediol. In addition, polyol may be used independently or 2 or more types may be used together.

Polyester polyol (A1) is microcrystalline. The microcrystalline polyester polyol (A1) refers to the endothermic amount of the melting curve measured at a heating rate of 10 ° C./min in the measurement of differential scanning calorimetry (DSC) specified in JIS K7121 (hereinafter simply “absorbed cal/g (10 J/g) or more and less than 10 cal/g (40 J/g).

The number average molecular weight of the microcrystalline polyester polyol (A1) is 3000 or more, preferably 3500 or more, more preferably 4000 or more. The number average molecular weight of the microcrystalline polyester polyol (A1) is 6000 or less, preferably 5000 or less, more preferably 4800 or less. When the number average molecular weight of the microcrystalline polyester polyol (A1) is 3000 or more, the resin adhesion of the moisture-curable hot-melt adhesive is improved. When the number-average molecular weight of the microcrystalline polyester polyol (A1) is 6000 or less, the moisture-curable hot-melt adhesive is improved in coatability.

In the present invention, the number average molecular weight of polyol refers to a value measured in the following manner. The number average molecular weight of polyols can be measured using a gel permeation chromatography (GPC) method. Specifically, a sample solution is prepared by dissolving the sample in tetrahydrofuran (THF) so as to have a concentration of 1.0% by mass. Using this sample solution, the number average molecular weight of the polyol is measured by the GPC method using a refractive index detector with standard polystyrene as a reference.

As a measurement device, for example, a system (all manufactured by Shimadzu Corporation) consisting of a liquid transfer device LC-9A, a refractive index detector RID-6A, a column oven CTO-6A, and a data analysis device C-R4A. can be used. As GPC columns, for example, three GPC-805 (exclusion limit 4,000,000) and one GPC-804 (exclusion limit 400,000) (all manufactured by Shimadzu Corporation) can be connected in this order and used. The measurement conditions are a sample injection volume of 25 μL (liter), an eluent of tetrahydrofuran (THF), a liquid feed rate of 1.0 mL/min, and a column temperature of 45°C.

The hydroxyl value of the microcrystalline polyester polyol (A1) is preferably 20 mgKOH/g or more, more preferably 21 mgKOH/g or more, more preferably 22 mgKOH/g or more, and more preferably 23 mgKOH/g or more. The hydroxyl value of the microcrystalline polyester polyol (A1) is preferably 50 mgKOH/g or less, more preferably 40 mgKOH/g or less, more preferably 35 mgKOH/g or less, and more preferably 30 mgKOH/g or less. It is preferable that the hydroxyl value of the microcrystalline polyester polyol (A1) is 20 mgKOH/g or more, since the resin adhesiveness of the moisture-curable hot-melt adhesive is improved. When the hydroxyl value of the microcrystalline polyester polyol (A1) is 50 mgKOH/g or less, the resin adhesion of the moisture-curable hot-melt adhesive is improved.

In the present invention, the hydroxyl value of a polyol means the number of mg of potassium hydroxide required to neutralize the acetic acid bound to the hydroxyl group when 1 g of the polyol is acetylated (JIS K0070: 19922 .1(5)). Specifically, it can be measured by acetylating the hydroxyl groups in the polyol with acetic anhydride and then titrating the unused acetic anhydride with potassium hydroxide (JIS K0070: 1992 3.1 (neutralization titration method)). .

The content of the microcrystalline polyester polyol (A1) in the polyol (A) is preferably 20% by mass or more, more preferably 25% by mass or more, and more preferably 30% by mass or more. In the polyol (A), the content of the microcrystalline polyester polyol (A1) is preferably 50% by mass or less, more preferably 48% by mass or less, and more preferably 45% by mass or less. When the content of the microcrystalline polyester polyol (A1) is 20% by mass or more, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved. When the content of the microcrystalline polyester polyol (A1) is 50% by mass or less, the wet heat adhesiveness of the moisture-curable hot-melt adhesive is improved.

When the polyol (A) further contains a crystalline polyester polyol (A4) and / or a polycarbonate polyol (A5), the content of the microcrystalline polyester polyol (A1) in the polyol (A) is When the total amount of polyester polyol (A1), liquid polyester polyol (A2), second polyol, crystalline polyester polyol (A4) and polycarbonate polyol (A5) is 100% by mass, it is preferably 20% by mass or more, and 25% by mass. The above is more preferable, and 30% by mass or more is more preferable. The content of microcrystalline polyester polyol (A1) is the total amount of microcrystalline polyester polyol (A1), liquid polyester polyol (A2), second polyol, crystalline polyester polyol (A4) and polycarbonate polyol (A5) to 100. When expressed as % by mass, it is preferably 50% by mass or less, more preferably 48% by mass or less, and more preferably 45% by mass or less. When the content of the microcrystalline polyester polyol (A1) is 20% by mass or more, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved. When the content of the microcrystalline polyester polyol (A1) is 50% by mass or less, the wet heat adhesiveness of the moisture-curable hot-melt adhesive is improved.

[Liquid polyester polyol (A2)]
Polyol (A) has a number average molecular weight of 1000 to 6000. Liquid polyester polyol (A2) (hereinafter sometimes simply referred to as "liquid polyester polyol") is preferably a condensation polymer of polycarboxylic acid and polyol. That is, the liquid polyester polyol (A2) is preferably a polymer obtained by condensation polymerization of a polycarboxylic acid and a polyol through an ester reaction between the carboxyl groups of the polycarboxylic acid and the hydroxyl groups of the polyol.

Polycarboxylic acids are not particularly limited, and examples include terephthalic acid, isophthalic acid, phthalic anhydride, 1,5-naphthalic acid, 2,6-naphthalic acid, cyclohexanedicarboxylic acid, cyclopentanedicarboxylic acid, succinic acid, and glutaric acid. acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decamethylenedicarboxylic acid, dodecamethylenedicarboxylic acid, etc., preferably adipic acid, sebacic acid, isophthalic acid, terephthalic acid, phthalic anhydride, More preferably, it contains acid, sebacic acid and isophthalic acid, or adipic acid, terephthalic acid and phthalic anhydride. In addition, polycarboxylic acid may be used independently or 2 or more types may be used together.

Polyols are not particularly limited, and examples include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 1 ,8-octanediol, 1,10-decanediol, diethylene glycol, cyclohexanediol and the like, preferably ethylene glycol, neopentyl glycol, 1,6-hexanediol, more preferably ethylene glycol, ethylene glycol, It preferably contains neopentyl glycol and 1,6-hexanediol. In addition, polyol may be used independently or 2 or more types may be used together.

The liquid polyester polyol (A2) is liquid at 1 atmosphere (1.013×10 ⁵ Pa) and 20°C.

The number average molecular weight of the liquid polyester polyol (A2) is 1000 or more, preferably 2000 or more, more preferably 2200 or more, more preferably 2700 or more, and more preferably 2800 or more. The number average molecular weight of the liquid polyester polyol (A2) is 6,000 or less, preferably 5,000 or less, more preferably 4,000 or less, and more preferably 3,800 or less. When the number average molecular weight of the liquid polyester polyol (A2) is 1000 or more, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved. When the number average molecular weight of the liquid polyester polyol (A2) is 6000 or less, the coatability of the moisture-curable hot-melt adhesive is improved.

The hydroxyl value of the liquid polyester polyol (A2) is preferably 20 mgKOH/g or more, more preferably 21 mgKOH/g or more, and even more preferably 22 mgKOH/g or more. The hydroxyl value of the liquid polyester polyol (A2) is preferably 50 mgKOH/g or less, more preferably 40 mgKOH/g or less, and more preferably 38 mgKOH/g or less. When the hydroxyl value of the liquid polyester polyol (A3) is 20 mgKOH/g or more, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved. When the hydroxyl value of the liquid polyester polyol (A3) is 50 mgKOH/g or less, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved.

In the polyol (A), the content of the liquid polyester polyol (A2) is preferably 10% by mass or more, more preferably 15% by mass or more, more preferably 20% by mass or more, and more preferably 25% by mass or more. The content of the liquid polyester polyol (A2) in the polyol (A) is preferably 50% by mass or less, more preferably 45% by mass or less, more preferably 40% by mass or less, and more preferably 38% by mass or less. When the content of the liquid polyester polyol (A2) is 10% by mass or more, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved. When the content of the liquid polyester polyol (A2) is 50% by mass or less, the wet heat adhesiveness of the moisture-curable hot-melt adhesive is improved.

When the polyol (A) further contains a crystalline polyester polyol (A4) and / or a polycarbonate polyol (A5), the content of the liquid polyester polyol (A2) in the polyol (A) is the microcrystalline polyester polyol When the total amount of (A1), the liquid polyester polyol (A2), the second polyol, the crystalline polyester polyol (A4) and the polycarbonate polyol (A5) is 100% by mass, it is preferably 10% by mass or more, and 15% by mass or more. It is more preferably 20% by mass or more, and more preferably 25% by mass or more. In the polyol (A), the content of the liquid polyester polyol (A2) is the microcrystalline polyester polyol (A1), the liquid polyester polyol (A2), the second polyol, the crystalline polyester polyol (A4) and the polycarbonate polyol (A5 ) is preferably 50% by mass or less, more preferably 45% by mass or less, more preferably 40% by mass or less, and more preferably 38% by mass or less, when the total amount of ) is 100% by mass. When the content of the liquid polyester polyol (A2) is 10% by mass or more, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved. When the content of the liquid polyester polyol (A2) is 50% by mass or less, the wet heat adhesiveness of the moisture-curable hot-melt adhesive is improved.

[Second polyol]
The second polyol contains at least one polyol selected from the group consisting of polyether polyols (A3) having a number average molecular weight of 500 to 7,000 and castor oil polyols (A6).

[Polyether polyol (A3)]
Polyol (A) contains a polyether polyol (A3) having a number average molecular weight of 500 to 7000 (hereinafter sometimes simply referred to as "polyether polyol (A3)"). The polyether polyol (A3) is not particularly limited. As the polyether polyol (A3), (1) general formula: HO-(R ¹ -O)p- (wherein R ¹ represents an alkylene group having 1 to 14 carbon atoms, p is a repeating unit (2) an alkylene oxide (e.g., ethylene oxide, propylene oxide, butylene oxide, isobutylene oxide) in the active hydrogen portion of the bisphenol A molecular skeleton; etc.) is preferred. The main chain skeleton of the polyether polyol (A3) may consist of only one type of repeating unit, may contain two or more types of repeating units, or may contain two or more types of polymer blocks. good too. The polyether polyol (A3) may be used alone or in combination of two or more.

In the present invention, the alkylene group is a divalent atomic group generated by excluding two hydrogen atoms bonded to two different carbon atoms in an aliphatic saturated hydrocarbon, both linear and branched contains the atomic group of The term "branched" includes the case where one carbon (methyl group) is bonded as a side chain.

Examples of the alkylene group include an ethylene group, a propylene group [--CH ₍ CH.sub.3)--CH.sub.2--], a trimethylene group [ _--CH.sub.2 -- _CH.sub.2 -- _CH.sub.2-- ], a butylene group and an _amylene group [-- ₍ CH.sub.2--]. ) _5- ], hexylene group, and the like.

Examples of [-(R ¹ -O)p-] of the polymer containing the repeating unit represented by the above general formula: HO-(R ¹ -O)p- include polyethylene oxide, polypropylene oxide, poly butylene oxide, polytetramethylene oxide, polyethylene oxide-polypropylene oxide copolymer, and polypropylene oxide-polybutylene oxide copolymer. Among them, polypropylene oxide and polyethylene oxide-polypropylene oxide copolymers are preferable because they improve the wet heat adhesiveness of moisture-curable hot-melt adhesives.

The polyether polyol (A3) preferably contains a polypropylene triol represented by Formula 1 below. In Formula 1, R ⁴ , R ⁵ and R ⁶ each represent an alkylene group having 1 to 14 carbon atoms. R ⁴ , R ⁵ and R ⁶ may be the same or different. Each of x, y and z is the number of repeating units and is a positive integer.

Examples of the alkylene group include an ethylene group, a propylene group [--CH ₍ CH.sub.3)--CH.sub.2--], a trimethylene group [ _--CH.sub.2 -- _CH.sub.2 -- _CH.sub.2-- ], a butylene group and an _amylene group [-- ₍ CH.sub.2--]. ) _5- ], hexylene group, and the like.

As a polyether polyol obtained by addition reaction of alkylene oxide to the active hydrogen portion of the bisphenol A molecular skeleton, propylene A polyether polyol obtained by addition reaction of an oxide and a polyether polyol obtained by addition reaction of ethylene oxide to an active hydrogen portion of the bisphenol A molecular skeleton are preferred.

The number average molecular weight of the polyether polyol (A3) is 500 or more, preferably 600 or more, more preferably 650 or more, more preferably 700 or more, more preferably 750 or more, and more preferably 760 or more. The number average molecular weight of the polyether polyol (A3) is 7000 or less, preferably 6000 or less, more preferably 5000 or less, more preferably 4000 or less, more preferably 3000 or less, more preferably 2500 or less, and more preferably 2000 or less. Preferably, 1500 or less is more preferable. When the number average molecular weight of the polyether polyol (A3) is 500 or more, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved, which is preferable. When the polyether polyol (A3) has a number average molecular weight of 7,000 or less, the moisture-curable hot-melt adhesive is improved in coatability.

The hydroxyl value of the polyether polyol (A3) is preferably 50 mgKOH/g or more, more preferably 80 mgKOH/g or more, and more preferably 100 mgKOH/g or more. The hydroxyl value of the polyether polyol (A3) is preferably 200 mgKOH/g or less, more preferably 180 mgKOH/g or less, and more preferably 170 mgKOH/g or less. When the hydroxyl value of the polyether polyol (A3) is 50 mgKOH/g or more, the wet heat adhesiveness of the moisture-curable hot-melt adhesive is improved. When the hydroxyl value of the polyether polyol (A3) is 200 mgKOH/g or less, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved.

In the polyol (A), the content of the polyether polyol (A3) is preferably 1% by mass or more, more preferably 1.1% by mass or more, more preferably 1.2% by mass or more, and 1.5% by mass. The above is more preferable. In the polyol (A), the content of the polyether polyol (A3) is preferably 5% by mass or less, more preferably 4% by mass or less, more preferably 3% by mass or less, and more preferably 2.5% by mass or less. . When the content of the polyether polyol (A3) is 1% by mass or more, the wet heat adhesiveness of the moisture-curable hot-melt adhesive is improved. When the content of the polyether polyol (A3) is 5% by mass or less, the resin adhesion of the moisture-curable hot-melt adhesive is improved, and the thermal stability of the moisture-curable hot-melt adhesive is improved. , it is possible to improve the coatability by suppressing the thickening at the time of coating.

When the polyol (A) further contains a crystalline polyester polyol (A4) and/or a polycarbonate polyol (A5), the content of the polyether polyol (A3) in the polyol (A) is the microcrystalline polyester polyol When the total amount of (A1), the liquid polyester polyol (A2), the second polyol, the crystalline polyester polyol (A4) and the polycarbonate polyol (A5) is 100% by mass, it is preferably 1% by mass or more, and 1.1% by mass. The above is more preferable, 1.2% by mass or more is more preferable, and 1.5% by mass or more is more preferable. In the polyol (A), the content of the polyether polyol (A3) is the microcrystalline polyester polyol (A1), the liquid polyester polyol (A2), the second polyol, the crystalline polyester polyol (A4) and the polycarbonate polyol (A5 ) is preferably 5% by mass or less, more preferably 4% by mass or less, more preferably 3% by mass or less, and more preferably 2.5% by mass or less, when the total amount of ) is 100% by mass. When the content of the polyether polyol (A3) is 1% by mass or more, the wet heat adhesiveness of the moisture-curable hot-melt adhesive is improved. When the content of the polyether polyol (A3) is 5% by mass or less, the resin adhesion of the moisture-curable hot-melt adhesive is improved, and the thermal stability of the moisture-curable hot-melt adhesive is improved. , it is possible to improve the coatability by suppressing the thickening at the time of coating.

[Castor oil polyol (A6)]
Sunflower oil polyol is a polyol obtained by reacting the carboxy group of ricinoleic acid, which is a monocarboxylic acid, with the hydroxyl group of glycerin, and has a plurality of hydroxyl groups derived from glycerin hydroxyl group and / or ricinoleic acid in the molecule. doing. The sunflower oil polyol preferably has an average of 2 to 3 hydroxyl groups per molecule because it improves wet heat adhesion.

The castor oil polyol (A6) has a number average molecular weight of 500 or more, preferably 600 or more, more preferably 650 or more, more preferably 700 or more, more preferably 750 or more, and more preferably 760 or more. The number average molecular weight of the castor oil polyol (A6) is 7000 or less, preferably 6000 or less, more preferably 5000 or less, more preferably 4000 or less, more preferably 3000 or less, more preferably 2500 or less, more preferably 2000 or less. , 1500 or less. When the number average molecular weight of the castor oil polyol (A6) is 500 or more, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved, which is preferable. When the castor oil polyol (A6) has a number average molecular weight of 7,000 or less, the moisture-curable hot-melt adhesive is improved in coatability.

The hydroxyl value of the castor oil polyol (A6) is preferably 50 mgKOH/g or more, more preferably 80 mgKOH/g or more, and even more preferably 100 mgKOH/g or more. The hydroxyl value of the castor oil polyol (A6) is preferably 200 mgKOH/g or less, more preferably 180 mgKOH/g or less, and more preferably 170 mgKOH/g or less. When the hydroxyl value of the castor oil polyol (A6) is 50 mgKOH/g or more, the wet heat adhesiveness of the moisture-curable hot-melt adhesive is improved. When the hydroxyl value of the castor oil polyol (A6) is 200 mgKOH/g or less, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved.

In the polyol (A), the content of the castor oil polyol (A6) is preferably 1% by mass or more, more preferably 1.1% by mass or more, more preferably 1.2% by mass or more, and 1.5% by mass or more. is more preferred. In the polyol (A), the content of the castor oil polyol (A6) is preferably 5% by mass or less, more preferably 4% by mass or less, more preferably 3% by mass or less, and more preferably 2.5% by mass or less. When the content of the castor oil polyol (A6) is 1% by mass or more, the wet heat adhesiveness of the moisture-curable hot-melt adhesive is improved. When the content of the castor oil polyol (A6) is 5% by mass or less, the resin adhesion of the moisture-curable hot-melt adhesive is improved, and the thermal stability of the moisture-curable hot-melt adhesive is improved, It is possible to improve coatability by suppressing thickening during coating.

When the polyol (A) further contains a crystalline polyester polyol (A4) and / or a polycarbonate polyol (A5), the content of the castor oil polyol (A6) in the polyol (A) is the microcrystalline polyester polyol ( When the total amount of A1), the liquid polyester polyol (A2), the second polyol, the crystalline polyester polyol (A4) and the polycarbonate polyol (A5) is 100% by mass, it is preferably 1% by mass or more, and 1.1% by mass or more. is more preferable, 1.2% by mass or more is more preferable, and 1.5% by mass or more is more preferable. In the polyol (A), the content of the castor oil polyol (A6) is the microcrystalline polyester polyol (A1), the liquid polyester polyol (A2), the second polyol, the crystalline polyester polyol (A4) and the polycarbonate polyol (A5). 100% by mass, preferably 5% by mass or less, more preferably 4% by mass or less, more preferably 3% by mass or less, and more preferably 2.5% by mass or less. When the content of the castor oil polyol (A6) is 1% by mass or more, the wet heat adhesiveness of the moisture-curable hot-melt adhesive is improved. When the content of the castor oil polyol (A6) is 5% by mass or less, the resin adhesion of the moisture-curable hot-melt adhesive is improved, and the thermal stability of the moisture-curable hot-melt adhesive is improved, It is possible to improve coatability by suppressing thickening during coating.

Since the polyol (A) contains the microcrystalline polyester polyol (A1), the liquid polyester polyol (A2) and the second polyol, both the resin adhesion and the wet heat adhesion of the moisture-curable hot melt adhesive are improved. are improving.

Impairing either resin adhesion or wet heat adhesion in a moisture-curable hot-melt adhesive by using a combination of a prescribed microcrystalline polyester polyol (A1), a liquid polyester polyol (A2), and a second polyol. However, both resin adhesion and wet heat adhesion are improved.

In the polyol (A), polyester polyols other than microcrystalline polyester polyol (A1) and liquid polyester polyol (A2), polycarbonate polyols, polyether polyols ( Polyols other than A3), such as polyether polyols and polycaprolactone, may be contained.

[Crystalline polyester polyol (A4)]
Polyol (A) may contain a crystalline polyester polyol (A4). The crystalline polyester polyol (A4) is a condensation polymer of a polycarboxylic acid having 2 to 14 carbon atoms excluding the carbon in the carboxy group (-COOH) and a polyol having 2 to 8 carbon atoms. . That is, the crystalline polyester polyol (A4) is a polycarboxylic acid having 2 to 14 carbon atoms excluding carbon in the carboxy group and a polyol having 2 to 8 carbon atoms, and the carboxyl group of the polycarboxylic acid. It is a polymer obtained by condensation polymerization by causing an ester reaction at the hydroxyl groups of the polyol and polyol. The condensation polymerization reaction of polycarboxylic acid and polyol may be carried out using a general-purpose method. The number of carbon atoms excluding the carbon atoms in the carboxy groups defined in the polycarboxylic acid refers to the number of carbon atoms obtained by subtracting the total number of carbon atoms in all carboxy groups from the total number of carbon atoms contained in the molecule.

In the polycarboxylic acid, the number of carbon atoms excluding carbon atoms in the carboxy group is preferably 2 or more, more preferably 10 or more. In the polycarboxylic acid, the number of carbon atoms excluding carbon atoms in the carboxy group is preferably 14 or less, more preferably 12 or less. When the number of carbon atoms excluding carbon in the carboxy group is 2 or more, the crystallinity of the crystalline polyester polyol (A4) is improved, and the wet heat adhesiveness of the moisture-curable hot melt adhesive is improved, which is preferable. When the number of carbon atoms excluding carbon in the carboxy group is 14 or less, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved, which is preferable.

The polycarboxylic acid is preferably a divalent carboxylic acid (HOOC--R ² --COOH). A divalent carboxylic acid can reduce the melt viscosity of the moisture-curable hot-melt adhesive. The number of carbon atoms in R ² is preferably 2 or more, more preferably 10 or more. The carbon number of R ² is preferably 14 or less, more preferably 12 or less. When the number of carbon atoms in R ² is within the above range, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved.

R ² is preferably an aliphatic chain, more preferably a linear aliphatic chain. When R ² is an aliphatic chain, the crystallinity of the crystalline polyester polyol (A4) is improved and the resin adhesiveness of the moisture-curable hot-melt adhesive is improved, which is preferable. When R ² is linear, the crystallinity of the crystalline polyester polyol (A4) is improved, and the resin adhesiveness of the moisture-curable hot-melt adhesive is improved, which is preferable. The fact that R ² is linear means that the carbon atoms are linearly bonded without branching. R ² is preferably a linear alkylene group (--CnH ₂ n--). However, n is a natural number.

The polycarboxylic acid having 2 to 14 carbon atoms excluding the carbon in the carboxy group (—COOH) is not particularly limited, and examples thereof include sebacic acid, 1,12-dodecanedioic acid, decamethylene dicarboxylic acid (1, 10-decanedicarboxylic acid), 1,14-tetradecanedicarboxylic acid, etc. Sebacic acid, 1,12-dodecanedioic acid and decamethylenedicarboxylic acid are preferred. In addition, polycarboxylic acid may be used independently or 2 or more types may be used together.

The number of carbon atoms in the polyol is preferably 2 or more, more preferably 4 or more. The number of carbon atoms in the polyol is preferably 8 or less, more preferably 6 or less. When the number of carbon atoms in the polyol is 2 or more, the crystallinity of the crystalline polyester polyol (A4) is improved, and the wet heat adhesiveness of the moisture-curable hot melt adhesive is improved. When the number of carbon atoms in the polyol is 8 or less, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved.

The polyol is preferably a dihydric alcohol (HO--R ³ --OH). A dihydric alcohol can reduce the melt viscosity of the moisture-curable hot-melt adhesive. The carbon number of R ³ is preferably 2 or more, more preferably 4 or more. The number of carbon atoms in R ³ is preferably 8 or less, more preferably 6 or less. When the carbon number of R ³ is within the above range, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved.

R ³ is preferably an aliphatic chain, more preferably a linear aliphatic chain. When R ³ is an aliphatic chain, the crystallinity of the crystalline polyester polyol (A4) is improved and the resin adhesiveness of the moisture-curable hot-melt adhesive is improved, which is preferable. When R ³ is linear, the crystallinity of the crystalline polyester polyol (A4) is improved, and the resin adhesiveness of the moisture-curable hot-melt adhesive is improved, which is preferable. The fact that R ³ is linear means that the carbon atoms are linearly bonded without being branched. R ³ is preferably a linear alkylene group (--CmH ₂ m--). However, m is a natural number. m is preferably an even number because it improves the crystallinity of the crystalline polyester polyol (A4) and improves the wet heat adhesiveness of the moisture-curable hot-melt adhesive.

Polyols having 2 to 8 carbon atoms are not particularly limited, and include 1,2-ethanediol (ethylene glycol), 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1, 6-hexanediol, 1,7-heptanediol, 1,8-octanediol and the like, preferably 1,6-hexanediol and 1,2-ethanediol (ethylene glycol), and 1,6-hexanediol. more preferred. In addition, polyol may be used independently or 2 or more types may be used together.

The crystalline polyester polyol (A4) is crystalline. A crystalline polyester polyol is a differential scanning calorimetry (DSC) measurement defined in JIS K7121, in which the endothermic amount of the melting curve measured at a heating rate of 10° C./min is 10 cal/g (40 J/g) or more. is a polyester polyol.

The number average molecular weight of the crystalline polyester polyol (A4) is preferably 1000 or more, more preferably 1500 or more, more preferably 1800 or more, more preferably 2000 or more, more preferably 2500 or more, more preferably 2800 or more, and 2900 or more. is more preferred. The number average molecular weight of the crystalline polyester polyol (A4) is preferably 20,000 or less, more preferably 10,000 or less, more preferably 7,000 or less, more preferably 6,000 or less, more preferably 5,000 or less, more preferably 4,500 or less, and 4,000 or less. is more preferable, and 3500 or less is more preferable. When the number average molecular weight of the crystalline polyester polyol (A4) is 1000 or more, the resin adhesion of the moisture-curable hot-melt adhesive is improved. When the number average molecular weight of the crystalline polyester polyol (A4) is 20,000 or less, the coatability of the moisture-curable hot-melt adhesive is improved.

The hydroxyl value of the crystalline polyester polyol (A4) is preferably 20 mgKOH/g or more, more preferably 25 mgKOH/g or more, and even more preferably 30 mgKOH/g or more. The hydroxyl value of the crystalline polyester polyol (A4) is preferably 50 mgKOH/g or less, more preferably 45 mgKOH/g or less, more preferably 40 mgKOH/g or less, and more preferably 35 mgKOH/g or less. When the hydroxyl value of the crystalline polyester polyol (A4) is 20 mgKOH/g or more, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved. When the hydroxyl value of the crystalline polyester polyol (A4) is 50 mgKOH/g or less, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved.

In the polyol (A), the content of the crystalline polyester polyol (A4) is preferably 1% by mass or more, more preferably 5% by mass or more, more preferably 10% by mass or more, more preferably 15% by mass or more, 20% by mass or more is more preferable. The content of the crystalline polyester polyol (A4) in the polyol (A) is preferably 35% by mass or less, more preferably 33% by mass or less, more preferably 30% by mass or less, and more preferably 25% by mass or less. When the content of the crystalline polyester polyol (A4) is 1% by mass or more, the resin adhesion of the moisture-curable hot-melt adhesive is improved. When the content of the crystalline polyester polyol (A4) is 35% by mass or less, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved.

When the polyol (A) further contains a crystalline polyester polyol (A4) and / or a polycarbonate polyol (A5), the content of the crystalline polyester polyol (A4) in the polyol (A) is the same as the microcrystalline polyester When the total amount of the polyol (A1), the liquid polyester polyol (A2), the second polyol, the crystalline polyester polyol (A4) and the polycarbonate polyol (A5) is 100% by mass, it is preferably 1% by mass or more, and 5% by mass or more. is more preferably 10% by mass or more, more preferably 15% by mass or more, and more preferably 20% by mass or more. In the polyol (A), the content of the crystalline polyester polyol (A4) is the microcrystalline polyester polyol (A1), the liquid polyester polyol (A2), the second polyol, the crystalline polyester polyol (A4) and the polycarbonate polyol ( When the total amount of A5) is 100% by mass, it is preferably 35% by mass or less, more preferably 33% by mass or less, more preferably 30% by mass or less, and more preferably 25% by mass or less. When the content of the crystalline polyester polyol (A4) is 1% by mass or more, the resin adhesion of the moisture-curable hot-melt adhesive is improved. When the content of the crystalline polyester polyol (A4) is 35% by mass or less, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved.

[Polycarbonate polyol (A5)]
The polyol (A) may contain a polycarbonate polyol (A5) having a number average molecular weight of 500 to 4000 (hereinafter sometimes simply referred to as "polycarbonate polyol (A5)").

Polycarbonate polyols (A5) include, for example, polyhexamethylene carbonate polyols and polycyclohexanedimethylene carbonate polyols. Incidentally, the polycarbonate polyols may be used alone or in combination of two or more.

The number average molecular weight of the polycarbonate polyol (A5) is preferably 500 or more, more preferably 1000 or more, more preferably 1500 or more, more preferably 2000 or more, and more preferably 2500 or more. The number average molecular weight of the polycarbonate polyol is preferably 4000 or less, more preferably 3800 or less, and even more preferably 3700 or less. When the number average molecular weight of the polycarbonate polyol is 500 or more, the wet heat adhesiveness of the moisture-curable hot-melt adhesive is improved. When the polycarbonate polyol has a number average molecular weight of 4000 or less, the moisture-curable hot-melt adhesive is improved in coatability.

The hydroxyl value of the polycarbonate polyol (A5) is preferably 15 mgKOH/g or more, more preferably 20 mgKOH/g or more, and more preferably 25 mgKOH/g or more. The hydroxyl value of the polycarbonate polyol (A5) is preferably 50 mgKOH/g or less, more preferably 45 mgKOH/g or less, more preferably 40 mgKOH/g or less, and more preferably 35 mgKOH/g or less. When the hydroxyl value of the polycarbonate polyol (A5) is 15 mgKOH/g or more, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved. When the hydroxyl value of the polycarbonate polyol (A5) is 50 mgKOH/g or less, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved.

In the polyol (A), the content of the polycarbonate polyol (A5) is preferably 0.5% by mass or more, more preferably 1% by mass or more, and more preferably 2% by mass or more. In the polyol (A), the content of the polycarbonate polyol (A5) is preferably 20% by mass or less, more preferably 18% by mass or less, more preferably 15% by mass or less, more preferably 11% by mass or less, and 8% by mass. % or less is more preferable. When the content of the polycarbonate polyol (A5) is 0.5% by mass or more, the wet heat adhesiveness of the moisture-curable hot-melt adhesive is improved. When the content of the polycarbonate polyol (A5) is 20% by mass or less, the wet heat adhesiveness of the moisture-curable hot-melt adhesive is improved.

When the polyol (A) further contains the crystalline polyester polyol (A4) and/or the polycarbonate polyol (A5), the content of the polycarbonate polyol (A5) in the polyol (A) is the microcrystalline polyester polyol ( When the total amount of A1), the liquid polyester polyol (A2), the second polyol, the crystalline polyester polyol (A4) and the polycarbonate polyol (A5) is 100% by mass, it is preferably 0.5% by mass or more, and 1% by mass or more. is more preferable, and 2% by mass or more is more preferable. In the polyol (A), the content of the polycarbonate polyol (A5) is the microcrystalline polyester polyol (A1), the liquid polyester polyol (A2), the second polyol, the crystalline polyester polyol (A4) and the polycarbonate polyol (A5). 100% by mass, preferably 20% by mass or less, more preferably 18% by mass or less, more preferably 15% by mass or less, more preferably 11% by mass or less, and more preferably 8% by mass or less. When the content of the polycarbonate polyol (A5) is 0.5% by mass or more, the wet heat adhesiveness of the moisture-curable hot-melt adhesive is improved. When the content of the polycarbonate polyol (A5) is 20% by mass or less, the wet heat adhesiveness of the moisture-curable hot-melt adhesive is improved.

[Polyisocyanate compound (B)]
A moisture-curable hot-melt adhesive contains a urethane prepolymer, which is a reaction product of the polyol (A) and the polyisocyanate compound (B). The urethane prepolymer is produced by condensation polymerization of the polyol (A) and the polyisocyanate compound (B) while forming urethane bonds between the hydroxyl groups of the polyol (A) and the isocyanate groups of the polyisocyanate compound (B). It is a thing.

The polyisocyanate compound includes a first polyisocyanate compound containing diisocyanate and polymethylene polyphenyl polyisocyanate, and at least one second polyisocyanate selected from the group consisting of isocyanurate compounds and biuret-type polyisocyanates.

The polyisocyanate compound contains diisocyanate and polymethylene polyphenyl polyisocyanate as essential components, and also contains either one or both of an isocyanurate compound and biuret-type polyisocyanate.

[First polyisocyanate compound]
The polyisocyanate compound contains a first polyisocyanate comprising a diisocyanate and a polymethylene polyphenyl polyisocyanate.

The diisocyanate is not particularly limited. Isooxycyanate (TDI, 2,4, 2,6 or a mixture thereof), xylylene diisocyanate (XDI), 1,5-naphthalene diisocyanate (NDI), tetramethylxylene diisocyanate, phenylene diisocyanate, hexamethylene diisocyanate (HDI) ), dimer acid diisocyanate, norbornene diisocyanate, lysine diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, isophorone diisocyanate (IPDI), hydrogenated diphenylmethane diisocyanate (hydrogenated MDI), hydrogenated xylylene diisocyanate (hydrogenated XDI), cyclohexane Examples include diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, etc. Polyisocyanate compounds containing aromatic rings (eg, benzene ring, naphthalene ring, etc.) are preferred. The diisocyanate is preferably diphenylmethane diisocyanate or carbodiimide-modified MDI, more preferably diphenylmethane diisocyanate, because it improves the resin adhesion of the moisture-curable hot-melt adhesive. In addition, diisocyanate may be used independently or 2 or more types may be used together.

The polymethylene polyphenyl polyisocyanate is represented by the following formula 2 and has 3 or more isocyanate groups in the molecule. In Formula 2, q is a natural number, preferably a natural number of 1-5. The polymethylene polyphenyl polyisocyanate may be used alone or in combination of two or more.

By using polymethylene polyphenyl polyisocyanate, it is possible to improve the cross-linking density of the cured product of the moisture-curable hot-melt adhesive, thereby improving wet heat adhesion.

[Second polyisocyanate compound]
The second polyisocyanate compound contains at least one polyisocyanate compound selected from the group consisting of isocyanurate compounds and biuret-type polyisocyanates.

The second polyisocyanate compound contains either one or both of an isocyanurate compound and a biuret-type polyisocyanate.

[Isocyanurate compound]
The isocyanurate compound used in the moisture-curable hot-melt adhesive is a trimer of diisocyanate, has a cyclic skeleton, and contains multiple (preferably three) isocyanate groups in the molecule. By incorporating an isocyanurate compound into the polyisocyanate compound, the wet heat adhesiveness of the moisture-curable hot-melt adhesive is improved. Incidentally, the isocyanurate compounds may be used alone or in combination of two or more.

The isocyanurate compound is a diisocyanate trimer, but the diisocyanate is not particularly limited. , carbodiimide-modified MDI, carbodiimidated diphenylmethane isocyanate compound, tolylene diisocyanate (TDI, 2,4, 2,6 or a mixture thereof), xylylene diisocyanate (XDI), 1,5-naphthalene diisocyanate (NDI), Tetramethylxylene diisocyanate, phenylene diisocyanate, hexamethylene diisocyanate (HDI), dimer acid diisocyanate, norbornene diisocyanate, lysine diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, isophorone diisocyanate (IPDI), hydrogenated diphenylmethane diisocyanate (hydrogenated MDI) , hydrogenated xylylene diisocyanate (hydrogenated XDI), cyclohexane diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and the like.

[Biuret-type polyisocyanate]
A biuret-type polyisocyanate is a polyisocyanate having a structure represented by the following formula (3) in its molecule and having a plurality of isocyanate groups.

As the biuret-type polyisocyanate, a polyisocyanate in which —R ⁷ —NCO is bonded to each nitrogen atom of formula (3) is preferred. ^R7 is an alkylene group.

Examples of the alkylene group include an ethylene group, a propylene group [--CH ₍ CH.sub.3)--CH.sub.2--], a trimethylene group [ _--CH.sub.2 -- _CH.sub.2 -- _CH.sub.2-- ], a butylene group and an _amylene group [-- ₍ CH.sub.2--]. ) _5- ], hexylene group, and the like.

In the urethane prepolymer, the content of diisocyanate units is preferably 9% by mass or more, more preferably 10% by mass or more, and more preferably 11% by mass or more. In the urethane prepolymer, the content of diisocyanate units is more preferably 20% by mass or less, more preferably 13% by mass or less. When the content of the diisocyanate unit is 9% by mass or more, the resin adhesion of the moisture-curable hot-melt adhesive is improved. When the diisocyanate unit content is 20% by mass or less, the moisture-curable hot-melt adhesive has improved resin adhesiveness.

In the urethane prepolymer, the content of polymethylene polyphenyl polyisocyanate is preferably 1% by mass or more, more preferably 2% by mass or more, more preferably 3% by mass or more, and more preferably 4% by mass or more. The content of polymethylene polyphenyl polyisocyanate is preferably 10% by mass or less, more preferably 8% by mass or less, and more preferably 6.5% by mass or less. When the content of polymethylene polyphenyl polyisocyanate is 1% by mass or more, the crosslink density of the cured product of the moisture-curable hot-melt adhesive is improved, and the wet-heat adhesiveness of the moisture-curable hot-melt adhesive is improved. When the content of polymethylene polyphenyl polyisocyanate is 10% by mass or less, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved.

In the urethane prepolymer, the content of the second polyisocyanate compound is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, more preferably 0.5% by mass or more, and 0.8% by mass or more. is more preferable, and 1% by mass or more is more preferable. The content of the second polyisocyanate compound is preferably 10% by mass or less, more preferably 8% by mass or less, more preferably 6% by mass or less, more preferably 4% by mass or less, more preferably 3% by mass or less. % by mass or less is more preferable. When the content of the second polyisocyanate compound is 1% by mass or more, the crosslink density of the cured product of the moisture-curable hot-melt adhesive is improved, and the wet-heat adhesiveness of the moisture-curable hot-melt adhesive is improved. When the content of the second polyisocyanate compound is 10% by mass or less, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved.

In the urethane prepolymer, the content of the isocyanurate compound is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, more preferably 0.5% by mass or more, and more preferably 0.8% by mass or more. Preferably, 1% by mass or more is more preferable. The content of the isocyanurate compound is preferably 10% by mass or less, more preferably 8% by mass or less, more preferably 6% by mass or less, more preferably 4% by mass or less, more preferably 3% by mass or less, and 2% by mass. The following are more preferred. When the content of the isocyanurate compound is 1% by mass or more, the crosslink density of the cured product of the moisture-curable hot-melt adhesive is improved, and the wet-heat adhesiveness of the moisture-curable hot-melt adhesive is improved. When the content of the isocyanurate compound is 10% by mass or less, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved.

In the urethane prepolymer, the content of the biuret-type polyisocyanate is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, more preferably 0.5% by mass or more, and 0.8% by mass or more. More preferably, it is 1% by mass or more. The content of the biuret-type polyisocyanate is preferably 10% by mass or less, more preferably 8% by mass or less, more preferably 6% by mass or less, more preferably 4% by mass or less, more preferably 3% by mass or less, and 2% by mass. % or less is more preferable. When the content of the biuret-type polyisocyanate is 1% by mass or more, the crosslink density of the cured product of the moisture-curable hot-melt adhesive is improved, and the wet-heat adhesiveness of the moisture-curable hot-melt adhesive is improved. When the content of the biuret-type polyisocyanate is 10% by mass or less, the resin adhesiveness of the moisture-curable hot-melt adhesive is improved.

[Additive]
Moisture-curing hot-melt adhesives contain tackifiers, oils, plasticizers, curing catalysts, stabilizers, fillers, antioxidants, light stabilizers, ultraviolet absorbers, and colorants within limits that do not impede their effects. , flame retardants, fragrances, pigments, and dyes.

The tackifier is not particularly limited, and examples thereof include rosin-based resins, terpene-based resins, aliphatic petroleum resins, and aromatic petroleum resins. In addition, a tackifier may be used independently or 2 or more types may be used together.

The ring and ball softening point of the tackifier is preferably 90 to 150° C., because it can prevent elution from the moisture-curable hot-melt adhesive at room temperature and sufficiently melt when the moisture-curable hot-melt adhesive melts. . The ring and ball softening point of a tackifier is a temperature measured according to JIS K6863 (as a measuring method, a ring filled with a sample is horizontally supported in a glycerin bath, and a ball placed in the center of the sample touches the bottom plate. (measure the temperature when the

The oil is not particularly limited, and examples thereof include aromatic components, naphthenic oils, paraffinic oils, etc. contained in known oils generally called process oils, extender oils, softeners, etc. as rubber softeners. mentioned. In addition, the oil may be used alone or in combination of two or more.

The plasticizer is not particularly limited. Aliphatic esters such as butyl oleate and methyl acetylricinoleate, trimellitic esters, chlorinated paraffins, hydrocarbon plasticizers such as alkyldiphenyl and partially hydrogenated terphenyl, process oils, epoxidation Soybean oil, epoxy plasticizers such as benzyl epoxy stearate, vinyl polymers obtained by polymerizing vinyl monomers, diethylene glycol dibenzoate, triethylene glycol dibenzoate, polyalkylene glycol esters such as pentaerythritol esters, etc. mentioned. The plasticizers may be used alone or in combination of two or more.

Curing catalysts are used to improve the curability of moisture-curable hot-melt adhesives. The curing catalyst is not particularly limited, and examples thereof include amine-based curing catalysts and tin-based curing catalysts. The curing catalyst may be used alone or in combination of two or more.

As the amine-based curing catalyst, morpholine-based compounds are preferred. Specifically, 2,2′-dimorpholinodiethyl ether, bis(2,6-dimethylmorpholinoethyl) ether, bis(2-(2,6-dimethyl -4-morpholino)ethyl)-(2-(4-morpholino)ethyl)amine, bis(2-(2,6-dimethyl-4-morpholino)ethyl)-(2-(2,6-diethyl-4- morpholino)ethyl)amine, tris(2-(4-morpholino)ethyl)amine, tris(2-(4-morpholino)propyl)amine, tris(2-(4-morpholino)butyl)amine, tris(2-( 2,6-dimethyl-4-morpholino)ethyl)amine, tris(2-(2,6-diethyl-4-morpholino)ethyl)amine, tris(2-(2-ethyl-4-morpholino)ethyl)amine, tris(2-(2-ethyl-4-morpholino)ethylamine and the like.

The tin-based curing catalyst is not particularly limited, and examples thereof include stannous acetate, dibutyltin dilaurate, dibutyltin dioctate, dibutyltin diacetate, dioctyltin dilaurate, dioctyltin dioctate, dioctyltin diacetate, and stannous dioctanoate. etc. These may be used alone or in combination of two or more.

The filler is not particularly limited, and examples thereof include silica, talc, clay, calcium carbonate, magnesium carbonate, anhydrous silicon, hydrous silicon, calcium silicate, titanium dioxide, carbon black, bentonite, organic bentonite, shirasu balloon, glass micro Balloons, organic microballoons such as phenol resin and vinylidene chloride resin, polyvinyl chloride (PVC) powder, resin powder such as polymethyl methacrylate powder, and the like can be used. In addition, a filler may be used individually or in combination of 2 or more types.

The antioxidant is not particularly limited, and examples thereof include hindered phenol-based antioxidants, monophenol-based antioxidants, bisphenol-based antioxidants, and polyphenol-based antioxidants. The antioxidants may be used alone or in combination of two or more.

The light stabilizer is not particularly limited, and for example, a hindered amine light stabilizer is preferable, and a hindered amine light stabilizer whose amine moiety is a tertiary amine is more preferable. Light stabilizers include, for example, N.I. N',N'',N'''-tetrakis-(4,6-bis-(butyl-(N-methyl-2,2,6,6-tetramethylpiperidin-4-yl)amino)-triazine- 2-yl)-4,7-diazadecane-1,10-diamine, decanedioic acid bis(2,2,6,6-tetramethyl-1(octyloxy)-4-piperidinyl) ester, 1,1-dimethyl Reaction product of ethyl hydroperoxide and octane, bis(1,2,2,6,6,-pentamethyl-4-piperidyl [[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl] methyl] butylmalonate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate, bis (1-octyloxy -2,2,6,6 tetramethyl-4-piperidyl) sebacate, etc. The light stabilizers may be used alone or in combination of two or more.

The ultraviolet absorber is not particularly limited, and examples thereof include benzotriazole-based ultraviolet absorbers and benzophenone-based ultraviolet absorbers. In addition, an ultraviolet absorber may be used independently or 2 or more types may be used together.

[Moisture curing hot melt adhesive]
The manufacturing method of the moisture-curable hot-melt adhesive is not particularly limited. The moisture-curable hot-melt adhesive can be produced by, for example, adding additives to the urethane prepolymer produced in the manner described above, heating and melting it, and uniformly mixing it. can be done.

The moisture-curable hot melt adhesive comprises a polyol (A) containing a first polyol and a second polyol containing a microcrystalline polyester polyol (A1) and a liquid polyester polyol (A2), diisocyanate and polymethylene polyphenyl polyisocyanate Since it contains a urethane prepolymer that is a reaction product of a first polyisocyanate compound containing and a second polyisocyanate compound containing The specific polyisocyanate compound (B) is used to improve the cross-linking density of the cured product of the moisture-curable hot-melt adhesive without impairing the effect of improving the properties of the moisture-curable hot-melt adhesive. It has wet heat adhesion.

The melt viscosity of the moisture-curable hot melt adhesive at 120° C. is preferably 5000 to 60000 mPa·s, more preferably 5500 to 55000 mPa·s, and even more preferably 6000 to 50000 mPa·s. When the moisture-curable hot-melt adhesive has a melt viscosity of 5000 mPa·s or more at 120° C., the moisture-curable hot-melt adhesive has improved coatability. When the moisture-curable hot-melt adhesive has a melt viscosity at 120° C. of 60000 mPa·s or less, the moisture-curable hot-melt adhesive has improved coatability. The melt viscosity of the moisture-curable hot-melt adhesive at 120° C. was determined using a Brookfield viscometer at a temperature of 120° C. and a rotation speed of 20 rpm according to the Japan Adhesive Industry Association Standard JAI-7-1999. It refers to the melt viscosity obtained by measuring with The B-type viscometer is commercially available, for example, from Brookfield under the trade name of "B-type viscometer digital rheometer DVII (rotor No. 29)".

Explain how to use the moisture-curable hot-melt adhesive. To use a moisture-curable hot-melt adhesive, heat the moisture-curable hot-melt adhesive to 70 to 160°C to melt it, and then apply the molten moisture-curable hot-melt adhesive to the substrate (adhering body) or topsheet (preferably topsheet) using conventional methods. A surface sheet is pasted onto a substrate via a moisture-curable hot-melt adhesive. Examples of applicators for applying a moisture-curable hot-melt adhesive in a molten state to a base material (adherend) or a surface sheet (preferably a surface sheet) include a roll coater, a spray coater, a T-die coater, and a knife. coater and the like.

After that, the moisture-curable hot-melt adhesive is preferably left in an environment of 20-25° C. and a relative humidity of 50-60% for 120-200 hours to remove the moisture-curable hot-melt adhesive from the air. , the base material (adherend) or the surface sheet or the like can be cured by moisture (moisture) contained in the surface sheet to bond and integrate the surface sheet onto the base material.

Moisture-curable hot-melt adhesives have excellent resin adhesion, so even if the surface of the base material is made of synthetic resin, the surface sheet can be firmly and integrally adhered to the surface of the base material. can be made

The material constituting the substrate or the surface of the substrate is not particularly limited, and examples thereof include polyvinyl chloride, polyvinylidene chloride, SPC, polyethylene, polypropylene, polystyrene, ABS, polyamide, polyester, polyurethane, polyvinyl alcohol, Synthetic resins such as ethylene-vinyl acetate copolymer resins, chlorinated polypropylenes, and melamine resins can be used.

Examples of the surface sheet include a decorative sheet. The decorative sheet is not particularly limited. A veneer, metal foil, etc. are mentioned. It should be noted that the decorative sheet may be made more decorative by adding a color or pattern to its surface.

Decorative materials obtained by integrally bonding a surface sheet to the surface of a base material using a moisture-curing hot-melt adhesive can be used, for example, for flooring, wooden door frames and panels, window frames, sills, handrails, and widths. It is preferably used as wood, peripherals, exterior materials such as kitchens, bathrooms, washstands and closets, interior materials and furniture.

Since moisture-curable hot-melt adhesives have excellent wet heat adhesion, decorative materials formed using moisture-curable hot-melt adhesives are often used in wet areas such as kitchens, bathrooms, and washbasins. Even if the surface sheet is peeled off from the base material, the unexpected situation of peeling of the topsheet from the base material hardly occurs, and the decorative material can maintain a beautiful appearance for a long period of time.

EXAMPLES The present invention will be described in more detail below using examples, but the present invention is not limited to these.

The polyols (A) and polyisocyanate compounds (B) used in Examples and Comparative Examples are shown below.

[Polyol (A)]
[First polyol]
[Microcrystalline polyester polyol (A1)]
Microcrystalline polyester polyol (A1) (trade name “HS 2H-458T” manufactured by Toyokuni Oil Co., Ltd., endothermic value: 6 cal/g, hydroxyl value: 25 mgKOH/g, number average molecular weight: 4500, adipic acid and terephthalic acid, Condensation polymer with 1,6-hexanediol)

[Liquid polyester polyol (A2)]
・Liquid polyester polyol (A21) (manufactured by Toyokuni Oil Co., Ltd., trade name "HS 2F-305S", liquid at 1 atmosphere (1.013 × 10 ⁵ Pa) and 20 ° C., hydroxyl value: 36 mg KOH / g, number average molecular weight: 3100, condensation polymers of ethylene glycol, neopentyl glycol and 1,6-hexanediol with adipic acid, sebacic acid and isophthalic acid)
・Liquid polyester polyol (A22) (manufactured by Toyokuni Oil Co., Ltd., trade name “HS Polyol 2000”, liquid at 1 atmosphere (1.013 × 10 ⁵ Pa) and 20 ° C., hydroxyl value: 32 mg KOH / g, number average molecular weight: 3500 , adipic acid, terephthalic acid, phthalic anhydride, and ethylene glycol)

[Second polyol]
[Polyether polyol (A3)]
Polyether polyol (A3) (trade name “Exenol 1030” manufactured by AGC, polypropylene triol, in formula 1, R ⁴ : propylene group, R ⁵ : propylene group, R ⁶ : propylene group, hydroxyl value: 160 mgKOH/g, Number average molecular weight: 1000)

[Castor oil polyol (A6)]
・ Castor oil polyol (A6) (trade name “TLM” manufactured by Toyokuni Oil Co., Ltd., reaction product of glycerin and ricinoleic acid, having an average of 2.7 hydroxyl groups in one molecule, hydroxyl value: 160 mg KOH / g, number Average molecular weight: 950)

[Crystalline polyester polyol (A4)]
・Crystalline polyester polyol (A41) (manufactured by Ube Industries, Ltd., trade name “Etanacol 3010”, endothermic value: 25 cal/g, hydroxyl value: 30 mgKOH/g, number average molecular weight: 3500, 1,12-dodecanedioic acid and 1, Condensation polymer with 6-hexanediol, carbon number excluding carbon in carboxy group in 1,12-dodecanedioic acid: 10, carbon number in 1,6-hexanediol: 6)
・Crystalline polyester polyol (A42) (trade name “Dynacol 7380” manufactured by Evonik Deguza, endothermic value: 25 cal/g, hydroxyl value: 30 mgKOH/g, number average molecular weight: 3500, 1,12-dodecanedioic acid and Condensation polymer with 1,6-hexanediol, carbon number excluding carbon in carboxy group in 1,12-dodecanedioic acid: 10, carbon number in 1,6-hexanediol: 6)

[Polycarbonate polyol (A5)]
Polycarbonate polyol (A5) (trade name “Etanacol UH-300” manufactured by Ube Industries, a condensation polymer of dimethyl carbonate and 1,6-hexanediol and having hydroxyl groups at both ends, hydroxyl value: 38 mgKOH/g , number average molecular weight: 3500)

[Flame retardants]
・Triphenyl phosphate

[Polyisocyanate compound (B)]
[Diisocyanate]
・4,4′-diphenylmethane diisocyanate (MDI)

[Polymethylene polyphenyl polyisocyanate]
・ Polymethylene polyphenyl polyisocyanate (crude MDI, q in formula 2: an integer of 1 to 5)

[Isocyanurate compound]
・ Isocyanurate compound 1 (trimer of hexamethylene diisocyanate (isocyanurate), product name “TPA-100” manufactured by Asahi Kasei Corporation)
・ Isocyanurate compound 2 (trimer of isophorone diisocyanate (isocyanurate), trade name “VESTANAT T 1890 SN” manufactured by Evonik Japan, 70% by mass solution, the amount of isocyanurate compound 2 only is shown in the table)

[Biuret-type polyisocyanate]
・ Biuret-type polyisocyanate (trade name “24A-100” manufactured by Asahi Kasei Corporation, HDI biuret-type polyisocyanate)

[Flame retardants]
・Triphenyl phosphate (TPP, manufactured by Daihachi Chemical Industry Co., Ltd., molecular weight: 326, melting point: 48.6 ° C.)

(Examples 1 to 23, Comparative Examples 1 to 4)
A predetermined amount of polyol (A) shown in Tables 1 to 3 is supplied to a 3-liter four-necked flask equipped with a stirring blade, heated to 120 ° C. to melt and mix, and then the pressure in the flask is reduced to 1 mmHg or less. Then, the polyol (A) was dehydrated. After purging the inside of the flask with nitrogen, the polyol (A) was kept at 80°C.

In the polyol (A), the content ratio (mass% ) are shown in Tables 1-3.

Into the flask, 4,4′-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate and isocyanurate compound as the polyisocyanate compound (B), and triphenyl phosphate were supplied, and under a nitrogen atmosphere, polyol (A) and the polyisocyanate compound (B) were reacted at 80° C. for 3 hours to produce a urethane prepolymer.

While the obtained urethane prepolymer was kept at 80° C., a predetermined amount of triphenyl phosphate shown in Table 1 was added as a flame retardant to the urethane prepolymer to produce a moisture-curable hot-melt adhesive. The resulting moisture-curable hot-melt adhesive was solid at 25°C.

The melt viscosities at 120° C. of the obtained moisture-curable hot-melt adhesives were measured in the manner described above, and the results are shown in Tables 1-3.

The obtained moisture-curable hot-melt adhesive was measured for normal heat-resistant creep (resin adhesion) and wet-heat continuous creep (wet-heat adhesion) in the following manner, and the results are shown in Tables 1 to 3.

[Normal heat resistance creep (resin adhesion)]
A moisture-curable hot-melt adhesive was heated to 120° C. to melt. A moisture-curable hot-melt adhesive in a molten state was coated on the entire surface of a polyolefin resin sheet having a flat rectangular shape (length 150 cm×width 50 cm) and thickness 180 μm in a coating thickness of 40 μm.

Next, on the surface of a plate-like base material made of SPC (Stone Plastic Composite) made of calcium carbonate and polyvinyl chloride whose surface temperature is kept at 40° C., a polyolefin resin sheet is coated with a moisture-curable hot-melt adhesive. After superimposing so that the base material side was formed, a rubber roll was rolled on the polyolefin resin sheet to prepare a laminated sheet. Strips 1 inch (2.54 cm) wide and 15 cm long were cut from the laminate sheets.

The obtained test piece was cured in an atmosphere of 23° C. and 55% relative humidity for one week to moisture-harden the moisture-curable hot-melt adhesive.

With the polyolefin resin sheet facing downward, the test piece was placed so that its main surface was horizontal. A load of 500 g/1 inch was applied to one end of the polyolefin resin sheet in the length direction, and while maintaining this state, the test piece was left in an atmosphere of 60 ° C. for 24 hours, and the polyolefin resin sheet was used as the base material. The length (mm) peeled from was measured. In Comparative Examples 1, 2 and 5, the polyolefin resin sheet peeled from the substrate over the entire length within 24 hours from the start of the test, so the measurement could not be performed.

[Wet heat continuous creep (wet heat adhesion)]
A test piece was prepared in the same manner as for measurement of normal heat resistant creep. With the polyolefin resin sheet facing downward, the test piece was placed so that its main surface was horizontal. A load of 70 g/25 mm is applied to one end of the polyolefin resin sheet in the length direction, and while maintaining this state, the test piece is left in an atmosphere of 85 ° C. and a relative humidity of 85% for 30 days. The length (peeling length) (mm) of the sheet peeled from the substrate was measured. In Comparative Examples 1 to 4, the polyolefin resin sheet was peeled off from the substrate over the entire length within 30 days from the start of the test, so the measurement could not be performed.

After 30 days from the start of the test, the test pieces in which part of the polyolefin resin sheet is attached to the base material are further left under the same conditions, and the polyolefin resin sheet is completely peeled off from the base material. The number of days (the number of days peeled off) was measured.

Claims (7)

A urethane prepolymer that is a reaction product of a polyol and a polyisocyanate compound and has an isocyanate group at the end,
The above polyols are a first polyol containing a microcrystalline polyester polyol having a number average molecular weight of 3000 to 6000 and a liquid polyester polyol having a number average molecular weight of 1000 to 6000, and a polyether polyol having a number average molecular weight of 500 to 7000. and at least one second polyol selected from the group consisting of castor oil polyols,
The polyisocyanate compound contains a first polyisocyanate compound containing diisocyanate and polymethylene polyphenyl isocyanate, and at least one second polyisocyanate compound selected from the group consisting of isocyanurate compounds and biuret-type polyisocyanates. Moisture-curing hot-melt adhesive characterized by: The moisture-curable type according to claim 1, wherein the polyol contains 20 to 50% by mass of the microcrystalline polyester polyol, 10 to 50% by mass of the liquid polyester, and 1 to 5% by mass of the second polyol. Hot melt adhesive. The polyol is a crystalline polyester polyol which is a condensation polymer of a polycarboxylic acid having 2 to 14 carbon atoms excluding carbon atoms in the carboxy group and a polyol having 2 to 8 carbon atoms, and a crystalline polyester polyol having a number average molecular weight of 500. 3. The moisture-curable hot-melt adhesive according to claim 1, further comprising a polycarbonate polyol having a molecular weight of ˜4000. When the total amount of the crystalline polyester polyol, the liquid polyester polyol, the second polyol, the crystalline polyester polyol, and the polycarbonate polyol is 100% by mass,
The polyol includes 20 to 50% by mass of the microcrystalline polyester polyol, 10 to 50% by mass of the liquid polyester polyol, 1 to 5% by mass of the second polyol, 1 to 35% by mass of the crystalline polyester polyol, and the polycarbonate polyol. 4. The moisture-curable hot-melt adhesive according to claim 3, containing 1 to 35% by mass. The urethane prepolymer contains 1 to 20% by mass of the diisocyanate unit, 1 to 10% by mass of the polymethylene polyphenyl isocyanate compound unit, and 0.1 to 10% by mass of the second polyisocyanate compound. The moisture-curable hot-melt adhesive according to any one of claims 1 to 4. The moisture-curable hot-melt adhesive according to any one of claims 1 to 5, wherein the polyether polyol contains polypropylene triol. The moisture-curable hot-melt adhesive according to any one of claims 1 to 6, which has a melt viscosity of 5,000 to 60,000 mPa·s at 120°C.