JP7459484B2 - Moisture-curable polyurethane hot melt resin composition, adhesive, construction member, and flash panel - Google Patents

Description

The present invention relates to a moisture-curable polyurethane hot melt resin composition, an adhesive, a construction component, and a flash panel.

Traditionally, in the field of building components such as doors, decorative fittings made by bonding a base material such as plywood, MDF (medium density fiberboard), or particle board with a surface material such as a decorative sheet have been widely used to meet the demands of improving aesthetics and durability, and it is common for such decorative fittings to be attached to both sides of a core material and used as building components (see, for example, Patent Document 1).

In addition, the core material is often hollow from the viewpoint of reducing weight and imparting heat insulation properties. Therefore, a temperature difference tends to occur between the inside (particularly the hollow part) and the outside of the building member, and dew condensation may occur in the summer and winter. When dew condensation is absorbed by a decorative feature member, the decorative feature member may be deformed such as warping or swelling due to differences in moisture absorption among the members constituting the decorative feature member. Therefore, in order to suppress the warping and swelling of decorative fixtures and improve their durability, the provision of a moisture-proof layer inside decorative fixtures is being considered, and in particular, moisture-curing types that combine a moisture-proof layer and an adhesive are being considered. The use of polyurethane hot-melt resin compositions is being considered to reduce the number of moisture-proof sheets and the process of adhering the sheets.

JP 2016-74826 A

The problem to be solved by the present invention is to provide a moisture-curable polyurethane hot melt resin composition that has excellent initial adhesion, moisture resistance, and open time.

The present invention is a moisture-curable polyurethane hot melt resin composition containing a urethane prepolymer having an isocyanate group which is a reaction product of a polyol (a) and a polyisocyanate (b), wherein the polyol (a) is An object of the present invention is to provide a moisture-curable polyurethane hot melt resin composition, which is characterized by containing an alicyclic polyester polyol (a1) having a number average molecular weight of more than 1,000, which is made from added phthalic anhydride.

The present invention also provides an adhesive containing the moisture-curable hot melt resin composition, and a feature member and flash panel having an adhesive layer formed from the adhesive.

The moisture-curable polyurethane hot melt resin composition of the present invention has excellent adhesion, moisture resistance, and open time.

Therefore, the moisture-curable polyurethane hot melt resin composition of the present invention can be suitably used as an adhesive for laminating decorative boards. In addition, the obtained decorative boards and flash panels can be used as floor materials; doors such as foot doors, closet doors, and kitchen doors; fixture materials such as frame materials, picture frames, and baseboards; It can be suitably used for plates, etc.

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

It is essential that the polyol (a) contains an alicyclic polyester polyol (a1) having a number average molecular weight of more than 1,000, which is made from hydrogenated phthalic anhydride.

The alicyclic polyester polyol (a1) is made from hydrogenated phthalic anhydride and has a number average molecular weight of more than 1,000, which improves cohesive force and provides excellent initial adhesion and moisture resistance. He also has a reasonable amount of open time.

Specifically, as the alicyclic polyester polyol (a1), for example, a reaction product of the polybasic acid containing the hydrogenated phthalic anhydride and a compound having two or more hydroxyl groups can be used.

Examples of polybasic acids that can be used in addition to the hydrogenated phthalic anhydride include oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedicarboxylic acid, cyclohexanedicarboxylic acid, and cyclopropanedicarboxylic acid. , cyclobutanedicarboxylic acid, cyclopentanedicarboxylic acid, cycloheptanedicarboxylic acid, cyclooctanedicarboxylic acid, cyclononanedicarboxylic acid, cyclodecanedicarboxylic acid, cyclopropanetricarboxylic acid, clobutanetricarboxylic acid, cyclopentanetricarboxylic acid, cycloheptanetricarboxylic acid, Cyclohexanetricarboxylic acid, dicyclohexyl-4,4'-dicarboxylic acid, etc. can be used. These polybasic acids may be used alone or in combination of two or more. The content of the hydrogenated phthalic anhydride in the polybasic acid is preferably 70% by mass or more, more preferably 80% by mass or more.

Examples of the compound having two or more hydroxyl groups include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1, 2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 1,6-hexanediol, 2,5 -Hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 2-methyl- 1,3-propanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2- Methyl-1,8-octanediol, glycerin, trimethylolpropane, ditrimethylolpropane, tritrimethylolpropane, pentaerythritol, 1,2-cyclobutanediol, 1,3-cyclopentanediol, 1,4-cyclohexanediol, cycloheptane Diol, cyclooctanediol, 1,4-cyclohexanedimethanol, hydroxypropylcyclohexanol, tricyclo[5,2,1,0 ^2,6 ]decane-dimethanol, bicyclo[4.3,0]-nonanediol, diol Cyclohexanediol, tricyclo[5,3,1,1]dodecanediol, bicyclo[4,3,0]nonane dimethanol, tricyclo[5,3,1,1]dodecane-diethanol, hydroxypropyltricyclo[5,3 , 1,1] dodecanol, spiro[3,4]octanediol, butylcyclohexanediol, 1,1'-bicyclohexylidenediol, cyclohexanetriol, hydrogenated bisphenol A, 1,3-adamantanediol, etc. be able to. These compounds may be used alone or in combination of two or more.

The number average molecular weight of the alicyclic polyester polyol (a1) must exceed 1,000 in order to obtain excellent cohesive strength, and is preferably in the range of 1,500 to 50,000, and more preferably in the range of 1,700 to 10,000. The number average molecular weight of the alicyclic polyester polyol (a1) is a value measured by gel permeation chromatography (GPC).

The amount of the alicyclic polyester polyol (a1) to be used is from 20 to 20 based on the total mass of the polyol (a) and the polyisocyanate (b), in order to obtain even better initial adhesion and moisture resistance. A range of 70% by mass is preferred, and a range of 30 to 55% by mass is more preferred.

The polyol (a) can be a polyol other than the alicyclic polyester polyol (a1), such as a crystalline polyester polyol (a2), a polycaprolactone polyol (a3), an amorphous polyester polyol, or a polyacrylic polyol. , polycarbonate polyol, polyether polyol, etc. can be used. These polyols may be used alone or in combination of two or more. Among these, it is preferable to use crystalline polyester polyol (a2) and/or polycaprolactone polyol (a3) from the viewpoint of obtaining even better initial adhesion and open time. It is more preferable to use (a2) and polycaprolactone polyol (a3) together.

The crystalline polyester polyol (a2) can further improve the initial adhesion and open time (usable time), and can be, for example, a reaction product of a compound having two or more hydroxyl groups with a polybasic acid. In the present invention, "crystalline" refers to a material in which a peak of the heat of crystallization or heat of fusion can be confirmed in a DSC (differential scanning calorimeter) measurement in accordance with JIS K7121:2012, and "amorphous" refers to a material in which the peak cannot be confirmed.

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. etc. can be used. These compounds may be used alone or in combination of two or more. Among these, it is preferable to use one or more selected from the group consisting of butanediol, hexanediol, octanediol, and decanediol, from the viewpoint of increasing crystallinity and further improving initial adhesiveness and final adhesiveness.

As the polybasic acid, for example, oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, etc. can be used. These polybasic acids may be used alone or in combination of two or more. Among these, it is preferable to use one or more selected from the group consisting of adipic acid, sebacic acid, and dodecanedioic acid, from the viewpoint of increasing crystallinity and further improving initial adhesion and final adhesion.

In addition, as the crystalline polyester polyol (a2), it is more preferable to use a combination of a crystalline polyester polyol (a2-1) made from a polybasic acid having 11 or more carbon atoms and a crystalline polyester polyol (a2-2) made from a polybasic acid having less than 11 carbon atoms, in order to achieve both initial adhesive strength and open time.

The amount of the crystalline polyester polyol (a2) to be used is 5 out of the total mass of the polyol (a) and the polyisocyanate (b), from the viewpoint of obtaining even better initial adhesion and final adhesion. The range is preferably from 10 to 40% by weight, and more preferably from 10 to 35% by weight.

When the crystalline polyester polyol (a2-1) and the crystalline polyester polyol (a2-2) are used in combination, the mass ratio [(a2-1)/(a2-2)] is preferably in the range of 80/20 to 40/60, and more preferably in the range of 75/25 to 50/50.

The number average molecular weight of the crystalline polyester polyol (a2) is preferably in the range of 500 to 100,000, and more preferably in the range of 1,000 to 10,000, in order to further improve the initial adhesion and open time. The number average molecular weight of the crystalline polyester polyol (a2) is a value measured by gel permeation chromatography (GPC).

The polycaprolactone polyol (a3) can further improve initial adhesion and open time (usable time), and for example, the hydroxyl group that can be used as a raw material for the crystalline polyester polyol (a2). A reaction product of a compound having two or more of ε-caprolactone and ε-caprolactone can be used.

The number average molecular weight of the caprolactone polyol (a3) is preferably in the range of 20,000 to 200,000, and more preferably in the range of 30,000 to 100,000, in order to further improve the initial adhesion and open time. The number average molecular weight of the polycaprolactone polyol (a3) is a value measured by gel permeation chromatography (GPC).

The amount of the polycaprolactone polyol (a3) used is preferably in the range of 1 to 30% by mass, more preferably 3 to 20% by mass, of the total mass of the polyol (a) and the polyisocyanate (b), in order to further improve the initial adhesion and open time.

As the polyisocyanate (b), for example, aromatic diisocyanates such as diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate isocyanate, xylylene diisocyanate, phenylene diisocyanate, tolylene diisocyanate, and naphthalene diisocyanate; aliphatic or alicyclic diisocyanates such as hexamethylene diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and tetramethylxylylene diisocyanate can be used. These polyisocyanates may be used alone or in combination of two or more. Among these, aromatic polyisocyanates are preferred, and diphenylmethane diisocyanate is more preferred, in that they provide even better reactivity and adhesion.

The urethane prepolymer is a reaction product of the polyol (a) and the polyisocyanate (b), and has isocyanate groups that can react with moisture present in the air or in the substrate to which the urethane prepolymer is applied to form a crosslinked structure.

The urethane prepolymer can be produced, for example, by dropping a mixture of the polyol (a) into a reaction vessel containing the polyisocyanate (b), heating the mixture, and reacting the mixture under conditions in which the isocyanate groups of the polyisocyanate (b) are in excess of the hydroxyl groups of the polyol (a).

When producing the urethane prepolymer, the molar ratio (NCO/OH) of the hydroxyl group in the polyol (a) and the isocyanate group in the polyisocyanate (b) is reduced by reducing unreacted polyisocyanate, making it even better. From the viewpoint of obtaining good adhesion, the range is preferably from 1.5 to 7, more preferably from 1.8 to 3.

The isocyanate group content (hereinafter abbreviated as "NCO%") of the urethane prepolymer obtained by the above method should be in the range of 1 to 10% by mass in order to obtain even better adhesion. It is preferably in the range of 2 to 5% by mass, and even more preferably in the range of 2.5 to 4% by mass. Note that the NCO% of the urethane prepolymer is a value measured by potentiometric titration in accordance with JIS K1603-1:2007.

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

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

Next, the feature member of the present invention will be explained.

The feature member includes, for example, a base material, a sheet-like or film-like surface member, and an adhesive layer that adheres the base material and the surface member, and the adhesive layer includes the moisture-curable polyurethane hot It is formed by curing an adhesive containing a melt resin composition.

The feature member can be manufactured by bonding a base material described below and a sheet-like or film-like surface member using the moisture-curable polyurethane hot melt adhesive, for example, a floor material. Can be used for doors such as foot doors, closet doors, kitchen doors; fixture materials such as frame materials, picture frames, baseboards; and top plates such as counter tables and furniture top plates.

As the base material, for example, a wooden base material such as plywood, MDF (medium density fiberboard), particle board, or a metal base material such as aluminum or iron can be used. Furthermore, the base material may have complex-shaped portions such as grooves, R portions, and reverse R portions.

Examples of the sheet- or film-like surface member that can be used include sheets or films made of resins such as polyester, nylon, polystyrene, polycarbonate, vinyl chloride, ethylene-vinyl acetate copolymer, polyvinyl alcohol, polyethylene, and polypropylene, as well as paper, veneer, and metal foil. Among these, at least one selected from sheets or films made of polyvinyl chloride, sheets or films made of polyolefin, and sheets or films made of polyethylene terephthalate and paper are particularly preferably used.

The surface member may be plain or decorated with various colors, patterns, etc., and may be generally referred to as decorative paper, base paper for decorative laminates, decorative sheet, or the like. Furthermore, the back surface of the surface member, that is, the surface facing the base material, may be subjected to a primer treatment using a resin or the like.

As a method of bonding the base material and the surface member to form a feature member, for example, the moisture-curable polyurethane hot melt adhesive of the present invention is melted by heating within the range of 60 to 150 ° C. The moisture-curable polyurethane hot melt adhesive is applied onto the base material using a roll coater, spray coater, T-die coater, knife coater, etc., and the surface member is bonded to the coated surface, or melting is performed in the same manner as above. The moisture-curable polyurethane hot melt adhesive is applied onto the surface member using a roll coater, etc., a base material is bonded to the coated surface, and the base material is coated using a roll press, flat press, belt press, etc. Examples include a method of crimping as appropriate depending on the shape of the material.

The present invention also relates to a flush panel formed by bonding the above-mentioned fixtures to both sides of a core material. The flush panel of the present invention can be used for door materials, wall panels, ceiling panels, closet doors, partitions, desks, shelves, storage furniture, etc.

Table 1 is a sectional view showing an example of the structure of a flash panel according to the present invention. In the flash panel 200, a feature member 1 is formed by bonding surface members 14 and 15 to both surfaces of a base material 11 via adhesive layers 12 and 13, and a feature member 1 is formed by bonding surface members 14 and 15 to both surfaces of a base material 21 via adhesive layers 22 and 23. A feature member 2 in which film-like or sheet-like surface members 24 and 25 are bonded together is adhered to both surfaces of the core material 3. Although FIG. 1 shows a case where the feature member of the present invention is formed on both sides of the core material, the feature member of the present invention may be formed only on one side of the core material.

Wood materials such as tranboard, particle board, MDF (medium density fiberboard), metal materials such as aluminum, magnesium, steel plates, SUS, paper materials, etc. can be used. It is particularly preferable that the core material has a honeycomb structure since it is possible to reduce the weight of the flash panel and improve its heat insulation properties.

As a method for bonding a core material and a feature member to form a flash panel of the present invention, for example, the moisture-curing hot melt adhesive of the present invention may be coated with a roll coater, knife coater, bar coater, die coater, etc. A method can be used in which the core material is applied to a feature material and the core material and the feature member are bonded together by a method such as flat pressing, roll pressing, or belt pressing.

The present invention will be explained in more detail below using examples.

[Example 1]
A four-neck flask equipped with a thermometer, a stirrer, an inert gas inlet, and a reflux condenser was charged with 47 parts by mass of an alicyclic polyester polyol (a reaction product of hydrogenated phthalic anhydride and neopentyl glycol, number average molecular weight: 2,200, hereinafter abbreviated as "HHPA/NPG2200"), 20 parts by mass of a crystalline polyester polyol (a reaction product of 1,6-hexanediol and 1,12-dodecanedicarboxylic acid, number average molecular weight: 3,500, hereinafter abbreviated as "HG/DDA"), and 10 parts by mass of a polycaprolactone polyol (number average molecular weight: 80,000, hereinafter abbreviated as "PCL"), and dehydrated under reduced pressure conditions until the water content was 0.05% by mass or less.
Next, after cooling the temperature inside the container to 70°C, 23 parts by mass of 4,4'-diphenylmethane diisocyanate (hereinafter abbreviated as "MDI") was added, the temperature was raised to 100°C, and the reaction was carried out for about 3 hours until the NCO% became constant, thereby obtaining a moisture-curable urethane hot-melt resin composition containing a urethane prepolymer having an isocyanate group.

[Examples 2-4, Comparative Examples 1-2]
A urethane prepolymer was obtained in the same manner as in Example 1, except that the amounts of each raw material used were changed as shown in Table 1.

[Method for measuring number average molecular weight]
The number average molecular weights of the polyols used in Examples and Comparative Examples are values measured by gel permeation chromatography (GPC) 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 used by connecting them in series.
"TSKgel G5000" (7.8mm I.D. x 30cm) x 1 "TSKgel G4000" (7.8mm I.D. x 30cm) x 1 "TSKgel G3000" (7.8mm I.D. x 30cm) x 1 Book "TSKgel G2000" (7.8mm I.D. x 30cm) x 1 Detector: RI (differential refractometer)
Column temperature: 40℃
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL/min Injection volume: 100 μL (Tetrahydrofuran solution with sample concentration 0.4% by mass)
Standard sample: A calibration curve was created using the following standard polystyrene.

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

[Method for evaluating initial adhesion]
The moisture-curable polyurethane hot melt resin composition obtained in the examples and comparative examples was heated to a molten state at 120°C, the molten moisture-curable polyurethane hot melt resin composition was applied to a polyethylene terephthalate (PRT) sheet to a thickness of 50 μm, and then MDF (medium density fiberboard) was placed on the applied adhesive layer and bonded. After 3 minutes, a load of 100 g was applied to the bonded test piece in a 90° direction against a width of 25 mm in an atmosphere of 35°C, and the peel length of the PET sheet was measured after 15 minutes and evaluated as follows.
"T": The peel length is less than 5 mm.
"F": The peeling length is 5 mm or more.

[Method for evaluating moisture resistance]
A release film made of polyethylene terephthalate was placed on a glass plate whose surface temperature was adjusted to 100 ° C. A moisture-curable polyurethane hot melt resin composition heated and melted at 120 ° C. was applied to the release film using an applicator so that the film thickness was 100 μm, to prepare a coating. The coating was aged for one week under an atmosphere of a temperature of 30 ° C. and a relative humidity of 50%, and then the film formed from the moisture-curable polyurethane hot melt resin composition was peeled off from the release film to prepare a measurement sample. The moisture permeability of the measurement sample was measured (unit: g / m ² · 24 hr) based on the moisture permeability cup method (JIS-Z-0208-B method) and evaluated as follows.
"T": less than 15 (g/ ^m2 ·24hr).
"F": 15 (g/ ^m2 ·24hr) or more.

[Open time evaluation method]
The moisture-curable polyurethane hot melt adhesive obtained in the examples and comparative examples was heated to a molten state at 120°C and applied to a polypropylene sheet substrate to a thickness of 50 μm. Next, craft paper was placed as a surface member on the applied adhesive layer, and immediately left in a thermostatic chamber at 23°C. The time when the adhesive layer was left in the thermostatic chamber was set as the base point ( _T0 ), and the time until the craft paper no longer adhered to the adhesive layer (i.e., solidification time) ( _T1 , unit: seconds) was measured and defined as the "open time at 23°C". The open time was evaluated as follows.
"T": More than 4 minutes.
"F": Less than 4 minutes.

The abbreviations in Table 1 are as follows:
"HG/SEBA": Crystalline polyester polyol (reaction product of 1,6-hexanediol and sebacic acid, number average molecular weight: 3,500)
"NPG/oPA": amorphous polyester polyol (reaction product of neopentyl glycol and orthophthalic acid, number average molecular weight: 1,000)
"DEG/NPG/HG/AA": amorphous polyester polyol (reaction product of diethylene glycol, neopentyl glycol, 1,6-hexanediol, and adipic acid, number average molecular weight: 2,000)
"CHDA/NPG": alicyclic polyester polyol (reaction product of 1,4-cyclohexanedicarboxylic acid and neopentyl glycol, number average molecular weight: 1,000)
"HHPA/NPG1000": reaction product of hydrogenated phthalic anhydride and neopentyl glycol, number average molecular weight: 1,000

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

On the other hand, Comparative Example 1 is an embodiment in which a polyester polyol made from 1,4-cyclohexanedicarboxylic acid was used instead of the alicyclic polyester polyol (a1), but the moisture resistance and open time were poor.

Comparative Example 2 uses an alicyclic polyester polyol (a2) with a number average molecular weight below the range specified in the present invention, and the initial adhesion and open time were poor.

Claims (6)

A moisture-curable polyurethane hot melt resin composition containing a urethane prepolymer having an isocyanate group that is a reaction product of a polyol (a) and a polyisocyanate (b),
The polyol (a) contains an alicyclic polyester polyol (a1) made from hydrogenated phthalic anhydride and having a number average molecular weight of more than 1,000, and further contains a crystalline polyester polyol (a2) and a polyester polyester polyol (a2). A moisture-curable polyurethane hot-melt resin composition containing caprolactone polyol (a3). The moisture-curable polyurethane hot melt resin composition according to claim 1, wherein the amount of the alicyclic polyester polyol (a1) used is in the range of 20 to 70 mass % of the total mass of the polyol (a) and the polyisocyanate (b). The crystalline polyester polyol (a2) is a crystalline polyester polyol (a2-1) made from a polybasic acid having 11 or more carbon atoms, and a crystal made from a polybasic acid having less than 11 carbon atoms. The moisture-curable polyurethane hot-melt resin composition according to claim 1 , which is used in combination with a polyester polyol (a2-2). An adhesive comprising the moisture-curable polyurethane hot melt resin composition according to any one of claims 1 to 3 . A feature member comprising an adhesive layer made of the adhesive according to claim 4 . A flash panel characterized in that the feature member according to claim 5 is adhered to both sides of a core material.