JP2020094125A - Moisture-curable urethane hot-melt resin composition and laminate - Google Patents

Abstract

To provide a moisture-curable urethane hot-melt resin composition excellent in initial adhesive strength.SOLUTION: The present invention provides: a moisture-curable polyurethane hot-melt resin composition which contains an urethane prepolymer (i) having isocyanate groups and a photopolymerization initiator (ii), the urethane prepolymer (i) using as essential raw materials a polyol (A) containing a polycaprolactone polyol (a1), a polyisocyanate (B), and a compound (C) having one or more polymerizable unsaturated groups and two or more hydroxyl groups; and a laminate having a cured product layer of the moisture-curable polyurethane hot-melt resin composition. The urethane prepolymer (i) preferably has a polymerizable unsaturated group concentration in the range of 0.0004-2 mol/kg.SELECTED DRAWING: None

Description

The present invention relates to a moisture-curable urethane hot melt resin composition and a laminate.

Moisture-curable urethane hot melt resin composition containing urethane prepolymer as a main component is widely used for adhesion of metal materials, wood materials, plastics, rubber, textile products, synthetic leather, paper products, building material panels, It is used in various fields such as decorative boards, automobile interior materials, and clothing.

The characteristic of the moisture-curable urethane hot melt resin composition is that, like other hot melt adhesives, it is solventless, and in addition to the initial adhesive strength obtained by cooling and solidification, about 24 to 72 hours after adhesion. By reacting with the air or the humidity of the adherend within the time period, the final adhesive strength and heat resistance that cannot be exhibited by other hot melt adhesives can be obtained (see, for example, Patent Document 1). ). However, like other hot melt adhesives, it is not easy to further increase the initial adhesive strength only by cooling and solidifying.

JP, 2018-111748, A

The problem to be solved by the present invention is to provide a moisture-curable urethane hot melt resin composition having excellent initial adhesive strength.

The present invention relates to a polyol (A) containing a polycaprolactone polyol (a1), a polyisocyanate (B), and a compound (C) having one or more polymerizable unsaturated groups and two or more hydroxyl groups. Moisture-curable polyurethane hot-melt resin composition containing an isocyanate group-containing urethane prepolymer (i) and a photopolymerization initiator (ii) as essential materials, and a cured product layer thereof To provide a laminate having

The moisture-curable urethane hot melt resin composition of the present invention is excellent in initial adhesive strength and open time.

The moisture-curable urethane hot melt resin composition of the present invention has a polyol (A) containing a polycaprolactone polyol (a1), a polyisocyanate (B), and one or more polymerizable unsaturated groups, and a hydroxyl group. A urethane prepolymer (i) having an isocyanate group and a photopolymerization initiator (ii) as essential raw materials of a compound (C) having two or more of

The urethane prepolymer (i) has a polyol (A) containing the polycaprolactone polyol (a1), a polyisocyanate (B), one or more polymerizable unsaturated groups, and two or more hydroxyl groups. It is obtained by using the compound (C) as an essential raw material and has an isocyanate group.

The polycaprolactone polyol (a1) is an essential component for obtaining excellent initial adhesive strength. As the polycaprolactone polyol (a1), a reaction product of a compound having two or more hydroxyl groups and ε-caprolactone can be used.

Examples of the compound having two or more hydroxyl groups include ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, trimethylolpropane, trimethylolethane and glycerin. Can be used. These compounds may be used alone or in combination of two or more.

The number average molecular weight of the polycaprolactone polyol (a1) is preferably in the range of 20,000 to 200,000, more preferably in the range of 30,000 to 100,000, from the viewpoint of obtaining a more excellent initial adhesive strength. preferable. The number average molecular weight of the polycaprolactone polyol (a1) is a value measured by a gel permeation chromatography (GPC) method.

In addition to the alicyclic polyol (a1), the polyol (A) may be used in combination with other polyols if necessary.

Examples of the other polyols that can be used include crystalline polyester polyols, amorphous polyester polyols, polyether polyols, polycarbonate polyols, polyacrylic polyols, polyurethane polyols, polybutadiene polyols, hydrogenated polybutadiene polyols, and the like. These polyols may be used alone or in combination of two or more. Among these, it is preferable to use the crystalline polyester polyol from the viewpoint that even more excellent initial adhesive strength and final adhesive strength can be obtained.

The amount of the polycaprolactone polyol (a1) used in the polyol (A) is preferably 0.1% by mass or more, and 0.5 to 70, from the viewpoint of obtaining further excellent initial adhesive strength. The range of mass% is more preferable, the range of 1 to 50% by mass is further preferable, and the range of 2 to 40% by mass is particularly preferable.

Further, as the amount of the polycaprolactone polyol (a1) used, a total of 100 of the polyol (A), the polyisocyanate (B), and the compound (C) is used in order to obtain a more excellent initial adhesive strength. The amount is preferably 0.3 to 50 parts by mass, more preferably 0.5 to 40 parts by mass, and even more preferably 2 to 30 parts by mass with respect to parts by mass.

Examples of the polyisocyanate (B) include aliphatic polyisocyanates or alicyclic polyisocyanates such as hexamethylene diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and tetramethylxylylene diisocyanate; polymethylene polyphenyl polyisocyanate; Aromatic polyisocyanates such as diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate isocyanate, xylene diisocyanate, phenylene diisocyanate, tolylene diisocyanate, and naphthalene diisocyanate; these isocyanurates can be used. These polyisocyanates may be used alone or in combination of two or more. Among these, diphenylmethane diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and diisocyanurate are selected from the group consisting of these, because even more excellent reactivity and final adhesive strength are obtained. It is preferable to use one or more compounds.

As the amount of the polyisocyanate (B) used, the polyol (A), the polyisocyanate (B), the compound (C ) And 100 parts by mass in total, a range of 1 to 50 parts by mass is preferable, and a range of 10 to 40 parts by mass is more preferable.

The compound (C) has at least one polymerizable unsaturated group and at least two hydroxyl groups. By using this compound (C) as a raw material for the urethane prepolymer (i), a polymerizable unsaturated group can be introduced inside the molecule of the urethane prepolymer (i), and an excellent initial stage can be obtained by irradiation with ultraviolet rays or the like. Adhesive strength can be obtained. Furthermore, since the urethane prepolymer (i) has an isocyanate group at the molecular end, excellent final adhesive strength can be obtained by moisture curing.

Examples of the compound (C) include compounds represented by the following general formula (1), compounds represented by the following general formula (2), compounds represented by the following general formula (3), and general formula (4) below. The compound shown, the compound shown by the following general formula (5), the compound shown by the following general formula (6), and the like can be used.

（一般式（１）中、Ｒ^１は、炭素原子数１〜９の直鎖アルキレン基の側鎖に重合性不飽和基を含む原子団を１個以上有する構造を示す。）

(In the general formula (1), R ¹ represents a structure having at least one atomic group containing a polymerizable unsaturated group in the side chain of a linear alkylene group having 1 to 9 carbon atoms.)

（一般式（２）中、Ｒ^２及びＲ^４は、それぞれ独立してエチレン基の側鎖に重合性不飽和基を含む原子団を有する構造を示し、Ｒ^３は、炭素原子数１〜５のアルキレン基を示す。）

(In the general formula (2), R ² and R ⁴ each independently represent a structure having an atomic group containing a polymerizable unsaturated group in the side chain of an ethylene group, and R ³ represents 1 to 5 carbon atoms. The alkylene group of is shown.)

（一般式（３）中、Ｒ^５及びＲ^６は、それぞれ独立して水素原子又はメチル基を示し、ｎは１〜３の整数を示す。）

(In the general formula (3), R ⁵ and R ⁶ each independently represent a hydrogen atom or a methyl group, and n represents an integer of 1 to 3.)

（一般式（４）中、Ｒ^７は、水素原子又はメチル基を示し、ｎは２〜３の整数を示す。）

(In the general formula (4), R ⁷ represents a hydrogen atom or a methyl group, and n represents an integer of 2 to 3.)

（一般式（５）中、Ｒ^８、Ｒ^９、及び、Ｒ^１０は、それぞれ水素原子又はメチル基を示す。）

(In the general formula (5), R ⁸ , R ⁹ , and R ¹⁰ each represent a hydrogen atom or a methyl group.)

（一般式（６）中、Ｒ^１１、Ｒ^１２、Ｒ^１３、及び、Ｒ^１４は、それぞれ水素原子又はメチル基を示す。）

(In the general formula (6), R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ each represent a hydrogen atom or a methyl group.)

R ¹ in the general formula (1) represents a structure having two or more atomic groups containing a polymerizable unsaturated group in the side chain of a linear alkylene group having 1 to 9 carbon atoms. For example, pentaerythritol di(meth)acrylate has a structure in which R ¹ in the general formula (1) has two atomic groups containing a polymerizable unsaturated group in the side chain of a propylene group having 3 carbon atoms.

Specific examples of the compound represented by the general formula (1) include pentaerythritol di(meth)acrylate [dimethylolpropane di(meth)acrylate] and dimethylolmethane di(meth)acrylate (general formula (1) R ¹ therein has 3 carbon atoms and has two atomic groups having a polymerizable unsaturated group.), diethylolmethanedi(meth)acrylate, diethylolpropanedi(meth)acrylate (R ¹ in the general formula (1) has 5 carbon atoms and has two atomic groups having a polymerizable unsaturated group.), dipropanol methanedi(meth)acrylate, dipropanol. Propane di(meth)acrylate (R ¹ in the general formula (1) has 7 carbon atoms and has two atomic groups having a polymerizable unsaturated group), dibutanol methane di( (Meth)acrylate, dibutanolpropane di(meth)acrylate (R ¹ in the general formula (1) has 9 carbon atoms and has two atomic groups having a polymerizable unsaturated group.) Etc. can be used. These compounds may be used alone or in combination of two or more. Among these, it is preferable to use pentaerythritol di(meth)acrylate and/or dimethylolmethane di(meth)acrylate from the viewpoint of obtaining a more excellent initial adhesive strength.

In addition, in this invention, "(meth)acrylate" means either one or both of an acrylate and a methacrylate.

R ² and R ⁴ in the general formula (2) are structures having an atomic group containing a polymerizable unsaturated group in the side chain of the ethylene group. In the general formula (2), it has a total of two or more structures having an atomic group containing a polymerizable unsaturated group in the side chain of the ethylene group, and preferably has a structure of two or more and five or less, More preferably, it is in the range of 2 or more and 3 or less.

Further, R ³ in the general formula (2) represents an alkylene group having 1 to 5 carbon atoms, and examples thereof include a methylene group, an ethylene group, a propylene group, a butylene group, and a pentyl group.

Specific examples of the compound represented by the general formula (2) include, for example, bis(3-acryloyloxy-2-hydroxypropoxy)methane (R ² and R ⁴ in the general formula (2) have 2 carbon atoms. And has one atomic group having a polymerizable unsaturated group, and R ³ has one carbon atom.), 1,2-bis(3-acryloyloxy-2-hydroxypropoxy)ethane( R ² and R ⁴ in the general formula (2) have ² carbon atoms, and have one atomic group having a polymerizable unsaturated group, and R ³ has 2 carbon atoms. ), 1,3-bis(3-acryloyloxy-2-hydroxypropoxy)propane (R ² and R ⁴ in the general formula (2) are those each having 2 carbon atoms, and have an atomic group having a polymerizable unsaturated group. R ³ is one having ³ carbon atoms), 1,4-bis(3-acryloyloxy-2-hydroxypropoxy)butane (R ² and R ^{4 in the} general formula (2)). Has 2 carbon atoms and has one atomic group having a polymerizable unsaturated group, and R ³ has 4 carbon atoms.), 1,5-bis(3-acryloyloxy-) 2-Hydroxypropoxy)pentane (R ² and R ⁴ in the general formula (2) have ² carbon atoms, and have one atomic group having a polymerizable unsaturated group, and R ³ has a carbon atom. It is possible to use, for example, the number 5). These compounds may be used alone or in combination of two or more kinds. Among these, it is preferable to use 1,4-bis(3-acryloyloxy-2-hydroxypropoxy)butane from the viewpoint that even more excellent initial adhesive strength can be obtained.

The amount of the compound (C) used is 100 parts by mass of the total amount of the polyol (A), the polyisocyanate (B) and the compound (C) from the viewpoint of obtaining a more excellent initial adhesive strength. , Preferably 0.01 to 50 parts by mass, more preferably 0.5 to 30 parts by mass, further preferably 1 to 20 parts by mass, particularly preferably 3 to 15 parts by mass. ..

The urethane prepolymer (i) is obtained by reacting the polyol (A), the polyisocyanate (B) and the compound (C), and the hydroxyl group of the compound (C) is polyisocyanate (B). ), a polymerizable unsaturated group is introduced inside the molecule, and reacts with the water present in the air or the substrate to which the urethane prepolymer is applied to form a crosslinked structure. The compound has a reactive isocyanate group at the molecular end.

As a method for producing the urethane prepolymer (i), for example, polyisocyanate (B) is put into a reaction vessel containing the polyol (A) and the compound (C), and an isocyanate group contained in the polyisocyanate (B) is contained. Can be produced by reacting under a condition in which it is in excess of the hydroxyl groups of the polyol (A) and the compound (C).

The equivalent ratio (isocyanate group/hydroxyl group) between the isocyanate group of the polyisocyanate (B) and the hydroxyl group of the polyol (A) and the compound (C) when the urethane prepolymer (i) is produced is The range of 1.1 to 10 is preferable, and the range of 1.15 to 8 is more preferable, from the viewpoint that more excellent initial adhesive strength and final adhesive strength can be obtained.

The isocyanate group content of the urethane prepolymer (i) (hereinafter abbreviated as "NCO%") is in the range of 1 to 10% by mass from the viewpoint of obtaining a more excellent final adhesive strength. Are preferable, and the range of 1.5-8 mass% is more preferable. The NCO% of the urethane prepolymer (i) is a value measured by a potentiometric titration method based on JISK1603-1:2007.

The concentration of the polymerizable unsaturated group of the urethane prepolymer (i) is preferably 0.0004 to 2 mol/kg, more preferably 0.001 to 1 mol/kg. The concentration of the polymerizable unsaturated group in the urethane prepolymer (i) is a value calculated based on the reaction raw materials used.

Examples of the photopolymerization initiator (ii) include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and 1-[4-(2-hydroxyethoxy)phenyl]. 2-Hydroxy-2-methyl-1-propan-1-one, thioxanthone, thioxanthone derivative, 2,2-dimethoxy-1,2-diphenylethan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide , Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl)-butan-1-one and the like can be used. These photopolymerization initiators may be used alone or in combination of two or more kinds.

The amount of the photopolymerization initiator (ii) used is in the range of 0.0001 to 10 parts by mass with respect to 100 parts by mass of the urethane prepolymer (i), since further excellent ultraviolet curability can be obtained. Is preferable, and the range of 0.005 to 5 parts by mass is more preferable.

The moisture-curable urethane hot melt resin composition of the present invention contains the urethane prepolymer (i) and the photopolymerization initiator (ii) as essential components, but contains other additives as necessary. You may.

As the other additives, for example, a curing catalyst, a tackifier, a plasticizer, a light stabilizer, a filler, a dye, a pigment, an optical brightener, a silane coupling agent, a wax, a thermoplastic resin, or the like may be used. You can These additives may be used alone or in combination of two or more.

The melt viscosity of the moisture-curable urethane hot melt resin composition at 120° C. is preferably in the range of 8,000 to 500,000 mPa·s, from the viewpoint of obtaining a more excellent initial adhesive strength. The range of 2,000 to 200,000 mPa·s is more preferable, and the range of 25,000 to 150,000 mPa·s is further preferable. The melt viscosity of the moisture-curable urethane hot melt resin composition at 120°C is a value measured by a cone plate viscometer.

Next, the laminate of the present invention will be described.

The laminate of the present invention has a substrate and a cured product layer of the moisture-curable urethane hot melt resin composition.

Examples of the base material include wood base materials such as plywood, MDF (medium density fiber board) and particle board; metal base materials such as aluminum and iron; polyester, polyamide, polystyrene, polycarbonate, vinyl chloride, ethylene-vinyl acetate A sheet base material obtained by using a resin such as a polymer, polyvinyl alcohol, polyethylene, or polypropylene; a calcium silicate board; a paper; a metal foil; a veneer; a fiber base material such as a nonwoven fabric or a woven cloth; a synthetic leather; a paper; a rubber. Substrate: A glass substrate or the like can be used. The thickness of the base material is determined depending on the intended use, but is, for example, in the range of 1 to 500 mm.

As a method of applying the moisture-curable urethane hot melt resin composition onto the base material, for example, a moisture-curable urethane hot melt resin composition melted at 70 to 140° C. may be used in a roll coater, a spray coater, or a T coater. -Coater system such as tie coater, knife coater, comma coater; a method of applying to a substrate using a precision system such as dispenser, spray, inkjet printing, screen printing, offset printing, etc.

The cured product layer of the moisture-curable urethane hot melt composition is appropriately determined depending on the intended use, but is, for example, in the range of 0.001 to 3 cm.

The applied moisture-curable urethane hot melt composition can obtain excellent initial adhesive strength by irradiating with active energy rays. Examples of the active energy rays include ultraviolet rays, electron beams, X-rays, infrared rays, and visible rays. Among these, ultraviolet rays are preferable because the initial adhesive strength can be easily obtained.

When irradiating with the ultraviolet rays, for example, a light source such as a low pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a hydrogen lamp, a deuterium lamp, a halogen lamp, a xenon lamp, a carbon arc lamp, and a fluorescent lamp can be used.

The irradiation amount of the ultraviolet rays is 0.05 to 5 J/cm ² , more preferably 0.1 to 3 J/cm ² , and particularly preferably 0.3 to 1 from the viewpoint of obtaining a more excellent initial adhesive strength. The range is preferably 0.5 J/cm ² . The irradiation amount of the ultraviolet rays is based on a value measured in a wavelength range of 300 to 390 nm using a UV checker “UVR-N1” manufactured by GS Yuasa Co., Ltd.

After the ultraviolet irradiation, aging of the isocyanate group of the urethane prepolymer (i) is performed, and therefore, it is preferable to perform curing at a temperature of 10 to 40° C. for 1 to 3 days.

As described above, the moisture-curable urethane hot melt resin composition of the present invention is excellent in initial adhesive strength and open time.

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

[Example 1]
In a 2-liter 4-necked flask equipped with a stirrer and a thermometer, 3.4 parts by mass of dimethylolmethane diacrylate and polycaprolactone polyol (number average molecular weight: 80,000, hereinafter abbreviated as "PCL") 4 .1 part by mass and 77.7 parts by mass of another polyester polyol (reaction product of 1,6-hexanediol and adipic acid, number average molecular weight; 4,500, hereinafter abbreviated as "other PEs"), It was dehydrated under reduced pressure heating conditions until the water content in the flask was 0.05% by mass.
Then, after cooling to 70° C., 14.8 parts by mass of 4,4′-diphenylmethane diisocyanate (hereinafter abbreviated as “MDI”) was added, and the temperature was raised to 100° C., and then a photopolymerization initiator (1-hydroxycyclohexyl). 0.5 parts by mass of phenyl ketone (hereinafter abbreviated as “HCPK”) is added and reacted at 110° C. for about 3 hours under a nitrogen atmosphere until the content of the isocyanate group becomes constant, whereby the urethane prepolymer (i-1 ) (Polymerizable unsaturated group concentration; 0.31 mol/kg, NCO%; 2% by mass).

[Example 2]
In a 2 liter 4-necked flask equipped with a stirrer and a thermometer, 5.4 parts by mass of 1,4-bis(3-acryloyloxy-2-hydroxypropoxy)butane, 4.0 parts by mass of PCL, and other PEs 76.0. Then, the mixture was dehydrated under reduced pressure heating conditions until the water content in the flask was 0.05% by mass.
Then, after cooling to 70° C., 14.6 parts by mass of MDI was added, the temperature was raised to 100° C., 0.5 parts by mass of HCPK was added, and the mixture was heated at 110° C. under a nitrogen atmosphere until the isocyanate group content became constant. Urethane prepolymer (i-2) (polymerizable unsaturated group concentration: 0.31 mol/kg, NCO%; 2 mass%) was obtained by reacting for about 3 hours.

[Example 3]
In a 2-liter 4-necked flask equipped with a stirrer and a thermometer, compound (3-1) (in the general formula (3), R ⁵ represents a hydrogen atom, R ⁶ represents a methyl group, and n is an integer of 1. 5.2 parts by mass, 4.0 parts by mass of PCL, and 76.2 parts by mass of other PEs were charged, and the mixture was heated under reduced pressure until the water content in the flask became 0.05% by mass. Dehydrated.
Then, after cooling to 70° C., 14.7 parts by mass of MDI was added, the temperature was raised to 100° C., 0.5 parts by mass of HCPK was added, and the mixture was heated at 110° C. under a nitrogen atmosphere until the isocyanate group content became constant. Urethane prepolymer (i-3) (polymerizable unsaturated group concentration; 0.31 mol/kg, NCO%; 2 mass%) was obtained by reacting for about 3 hours.

[Example 4]
In a 2-liter 4-necked flask equipped with a stirrer and a thermometer, compound (3-2) (in the general formula (3), R ⁵ represents a methyl group, R ⁶ represents a hydrogen atom, and n is an integer of 1. 5.4 parts by mass of PCL, 4.0 parts by mass of PCL, and 76.0 parts by mass of other PEs are charged under reduced pressure heating conditions until the water content with respect to the total amount in the flask becomes 0.05% by mass. Dehydrated.
Then, after cooling to 70° C., 14.6 parts by mass of MDI was added, the temperature was raised to 100° C., 0.5 parts by mass of HCPK was added, and the mixture was heated at 110° C. under a nitrogen atmosphere until the isocyanate group content became constant. Urethane prepolymer (i-4) (polymerizable unsaturated group concentration: 0.31 mol/kg, NCO%; 2 mass%) was obtained by reacting for about 3 hours.

[Example 5]
Compound (4-1) (in the general formula (4), R ⁷ represents a hydrogen atom and n represents an integer of 3) was placed in a 2-liter 4-necked flask equipped with a stirrer and a thermometer. 4 parts by mass, 4.0 parts by mass of PCL and 76.0 parts by mass of other PEs were charged and dehydrated under reduced pressure heating conditions until the water content in the flask became 0.05% by mass.
Then, after cooling to 70° C., 14.6 parts by mass of MDI was added, the temperature was raised to 100° C., 0.5 parts by mass of HCPK was added, and the mixture was heated at 110° C. under a nitrogen atmosphere until the isocyanate group content became constant. Urethane prepolymer (i-5) (polymerizable unsaturated group concentration: 0.31 mol/kg, NCO%; 2%) was obtained by reacting for about 3 hours.

[Example 6]
In a 2 liter 4-necked flask equipped with a stirrer and a thermometer, compound (5-1) (in the general formula (5), R ⁸ represents a hydrogen atom, and R ⁹ and R ¹⁰ represent a methyl group.). 7.6 parts by mass of PCL, 1 part by mass of PCL and 76.7 parts by mass of other PEs were charged and dehydrated under reduced pressure heating conditions until the water content in the flask was 0.05% by mass.
Then, after cooling to 70° C., 14.7 parts by mass of MDI was added, the temperature was raised to 100° C., 0.5 parts by mass of HCPK was added, and the mixture was heated at 110° C. under a nitrogen atmosphere until the isocyanate group content became constant. Urethane prepolymer (i-6) (polymerizable unsaturated group concentration: 0.31 mol/kg, NCO%; 2 mass%) was obtained by reacting for about 3 hours.

[Example 7]
In a 2 liter 4-necked flask equipped with a stirrer and a thermometer, compound (5-1) (in the general formula (5), R ⁸ represents a hydrogen atom, and R ⁹ and R ¹⁰ represent a methyl group.). 7.6 parts by mass of PCL, 3.9 parts by mass of PCL and 74 parts by mass of other PEs were charged and dehydrated under reduced pressure heating conditions until the water content in the flask was 0.05% by mass.
Then, after cooling to 70° C., 14.5 parts by mass of MDI was added, the temperature was raised to 100° C., 0.5 parts by mass of HCPK was added, and the mixture was heated at 110° C. under a nitrogen atmosphere until the isocyanate group content became constant. Urethane prepolymer (i-7) (polymerizable unsaturated group concentration; 0.31 mol/kg, NCO%; 2.0 mass%) was obtained by reacting for about 3 hours.

[Example 8]
In a 2 liter 4-necked flask equipped with a stirrer and a thermometer, compound (5-1) (in the general formula (5), R ⁸ represents a hydrogen atom, and R ⁹ and R ¹⁰ represent a methyl group.). 7.7 parts by mass of PCL, 7.8 parts by mass of PCL, and 70.3 parts by mass of other PEs were charged and dehydrated under reduced pressure heating conditions until the water content in the flask was 0.05% by mass.
Then, after cooling to 70° C., 14.2 parts by mass of MDI was added, the temperature was raised to 100° C., 0.5 parts by mass of HCPK was added, and at 110° C. under a nitrogen atmosphere until the isocyanate group content became constant. Urethane prepolymer (i-8) (polymerizable unsaturated group concentration; 0.31 mol/kg, NCO%; 1.9 mass%) was obtained by reacting for about 3 hours.

[Example 9]
In a 2 liter 4-necked flask equipped with a stirrer and a thermometer, compound (5-1) (in the general formula (5), R ⁸ represents a hydrogen atom, and R ⁹ and R ¹⁰ represent a methyl group.). 7.6 parts by mass of PCL, 15.8 parts by mass of PCL, and 63.2 parts by mass of other PEs were charged and dehydrated under reduced pressure heating conditions until the water content with respect to the total amount in the flask was 0.05% by mass.
Then, after cooling to 70° C., 13.4 parts by mass of MDI was added, the temperature was raised to 100° C., 0.5 parts by mass of HCPK was added, and the mixture was heated at 110° C. under a nitrogen atmosphere until the isocyanate group content became constant. Urethane prepolymer (i-9) (polymerizable unsaturated group concentration; 0.31 mol/kg, NCO%; 1.8 mass%) was obtained by reacting for about 3 hours.

[Example 10]
Compound (6-1) (in the general formula (6), R ¹¹ , R ¹² , R ¹³ and R ¹⁴ all represent a methyl group) was placed in a 2-liter 4-necked flask equipped with a stirrer and a thermometer. 9.8 parts by mass of PCL, 3.8 parts by mass of PCL, and 72.2 parts by mass of other PEs were charged and dehydrated under reduced pressure heating conditions until the water content in the flask was 0.05% by mass.
Then, after cooling to 70° C., 14.3 parts by mass of MDI was added, the temperature was raised to 100° C., 0.5 parts by mass of HCPK was added, and at 110° C. under a nitrogen atmosphere until the isocyanate group content became constant. Urethane prepolymer (i-10) (polymerizable unsaturated group concentration: 0.31 mol/kg, NCO%; 1.9 mass%) was obtained by reacting for about 3 hours.

[Comparative Example 1]
A 2 liter 4-necked flask equipped with a stirrer and a thermometer was charged with 81.5 parts by mass of other PEs, and dehydrated under reduced pressure heating conditions until the water content in the flask was 0.05% by mass.
Then, after cooling to 70° C., 12.2 parts by mass of MDI was added, the temperature was raised to 100° C., 0.5 parts by mass of HCPK was added, and at 110° C. under a nitrogen atmosphere until the isocyanate group content became constant. Urethane prepolymer (iR-1) (polymerizable unsaturated group concentration; 0 mol/kg, NCO%; 2.2 mass%) was obtained by reacting for about 3 hours.

[Measurement method of number average molecular weight]
The number average molecular weights of the polyols and the like used in Synthesis Examples and Comparative Synthesis Examples are values measured by the gel permeation chromatography (GPC) method under the following conditions.

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

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

[Method of measuring melt viscosity at 120° C.]
The moisture-curable urethane hot melt resin compositions obtained in Examples and Comparative Examples were melted at 120° C. for 1 hour and then 1 ml was sampled and melted with a cone plate viscometer (40P cone, rotor rotation speed; 50 rpm). The viscosity was measured.

[Evaluation method of initial adhesive strength]
(1) Initial Peelability Test Method The moisture-curable urethane hot melt resin compositions obtained in Examples and Comparative Examples were each melted at 120° C. for 1 hour, and then a corona-treated polyethylene terephthalate group having a thickness of 200 μm was used. It was applied on the material using a roll coater so as to have a thickness of 100 μm. Then, the coated surface is irradiated with 0.65 J/cm ² of ultraviolet light using a high pressure mercury lamp, and a corona-treated polyethylene terephthalate (PET) substrate having a thickness of 200 μm is further bonded to the irradiated surface and bonded. After 3 minutes, the 180° peel strength (N/inch) was measured according to JIS K7311-1995 and evaluated as follows.
"A"; 70 N/inch or more "B"; 50 N/inch or more and less than 70 N/inch "C"; less than 50 N/inch

(2) Test method for initial heat-resistant creep resistance The moisture-curable urethane hot melt resin compositions obtained in Examples and Comparative Examples were each melted at 120° C. for 1 hour, and then a roll coater was placed on a polyethylene terephthalate substrate. It was applied to a thickness of 50 μm. Thereafter, the coated surface was irradiated with ultraviolet rays of 0.65 J/cm ² using a high pressure mercury lamp, and MDF (medium density fiber board) was placed on the irradiated surface and bonded. Five minutes after the bonding, in a 35° C. atmosphere, a load of 75 g was applied in a 90° direction with respect to a width of 25 mm, and the peeling length of the polyethylene terephthalate substrate after 15 minutes was measured and evaluated as follows. ..
"T"; less than 1 mm "F"; 1 mm or more and less than 5 mm "C"; 5 mm or more

It has been found that the moisture-curable urethane hot melt resin composition of the present invention has excellent initial adhesive strength.

On the other hand, in Comparative Example 1, the polycaprolactone polyol (A) and the compound (C) were not used, but the initial adhesive strength was poor.

Claims (5)

An essential raw material is a polyol (A) containing a polycaprolactone polyol (a1), a polyisocyanate (B), and a compound (C) having one or more polymerizable unsaturated groups and two or more hydroxyl groups. A moisture-curable polyurethane hot-melt resin composition comprising the urethane prepolymer (i) having an isocyanate group and a photopolymerization initiator (ii). The compound (C) is a compound represented by the following general formula (1), a compound represented by the following general formula (2), a compound represented by the following general formula (3), or a compound represented by the following general formula (4). The moisture-curable urethane hot melt resin composition according to claim 1, which is one or more selected from the group consisting of a compound represented by the following general formula (5) and a compound represented by the following general formula (6).

(In the general formula (1), R ¹ represents a structure having at least one atomic group containing a polymerizable unsaturated group in the side chain of a linear alkylene group having 1 to 9 carbon atoms.)

(In the general formula (2), R ² and R ⁴ each independently represent a structure having an atomic group containing a polymerizable unsaturated group in the side chain of an ethylene group, and R ³ represents 1 to 5 carbon atoms. The alkylene group of is shown.)

(In the general formula (3), R ⁵ and R ⁶ each independently represent a hydrogen atom or a methyl group, and n represents an integer of 1 to 3.)

(In the general formula (4), R ⁷ represents a hydrogen atom or a methyl group, and n represents an integer of 2 to 3.)

(In the general formula (5), R ⁸ , R ⁹ , and R ¹⁰ each represent a hydrogen atom or a methyl group.)

(In the general formula (6), R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ each represent a hydrogen atom or a methyl group.) The moisture-curable urethane hot melt resin composition according to claim 1 or 2, wherein the concentration of the polymerizable unsaturated group of the urethane prepolymer (i) is in the range of 0.0004 to 2 mol/kg. The moisture-curable urethane hot melt resin composition according to any one of claims 1 to 3, wherein the urethane prepolymer (i) has an isocyanate group content of 1 to 10% by mass. A laminate comprising a substrate and a cured product layer of the moisture-curable urethane hot melt resin composition according to any one of claims 1 to 4.